Focal accumulation of phosphorylated neurofilaments within anterior horn cell in familial amyotrophic lateral sclerosis

Summary Distribution of phosphorylated neurofilament proteins within anterior horn cells in three cases of familial and six cases of sporadic amyotrophic lateral sclerosis (ALS) and ten control cases were investigated by using a monoclonal antibody. Two distinct staining patterns of perikarya were observed; (1) homogeneous pattern; either the entire or a part of the perikaryon was immunostained homogeneously (homogeneously diffuse or partial pattern); (2) focal pattern: perikarya contained very distinct, inclusion-like focal accumulation of immunoreactive products of various morphologies such as round, ring-shaped, cord-like, tube-like and more irregular shapes. The homogeneous pattern was found in all three groups but was most common in sporadic ALS. On the other hand, the focal pattern was seen almost exclusively in familial ALS. The focal accumulation of neurofilaments appears at least in part to be related to the Lewy body-like hyaline inclusion which is known to contain neurofilaments. In addition, cord-like swellings of neurites in familial ALS also showed focal neurofilament accumulation. These observations suggest that the focal accumulation of phosphorylated neurofilaments is characteristic of familial ALS, although it may not be specific to the entity. The pathological process(es) producing the neurofilamentous abnormality may play an important role in anterior horn cell degeneration in familial ALS.     

Accumulation of neurofilaments in a sporadic case of amyotrophic lateral sclerosis

We report a case of sporadic amyotrophic lateral sclerosis (ALS) characterized by a marked accumulation of neurofilaments in the cytoplasm of neurons. The neurofilament was identified by immunohistochemical and electron microscopic studies. The distribution of the accumulation in this case was unique, not only in the motoneurons of the anterior horn but also in the neurons of the other areas of the spinal gray matter, some nuclei in the brain stem, pontine reticular formation, substantia nigra, dentate nucleus in the cerebellum and pyramidal cells in the motor cortex. These observations shed light on the pathogenesis of ALS.     

Synapse loss in anterior horn neurons in amyotrophic lateral sclerosis

This report deals with an ultrastructural investigation of the synapses of anterior horn neurons in the lumbar spinal cords of five patients with amyotrophic lateral sclerosis (ALS) who had mild neuronal depletion. Specimens from five age-matched, neurologically normal individuals served as controls. In each instance, the autopsy was performed within 3 h after death. A statistically significant decrease in cell body area, number of synapses and total synaptic length was found in the normal-appearing neurons of the ALS patients. The alterations were more pronounced in neurons with central chromatolysis. However, despite an approximately 20% reduction in the number of synapses, the length of the active synaptic zone of the normal-appearing neurons in the ALS patients was not diminished. This observation may be accounted for by a plasticity to the loss of synapses which maintained the active zone of the remaining synapses to increase synaptic efficiency. It is suggested that when the plasticity of the active zone reaches its limit, the continuing loss of synapses may lead to functional impairment. The capacity of the active synaptic zone to respond to progressive denervation of the anterior horn neurons may preserve motor function or slow the development of motor deficits in the early stage of degeneration of the lower motor neurons.Supported by a grant-in-aid for General Scientific Research (C) from the Japanese Ministry of Education, Science and Culture, and a research grant for New Drug Development in ALS from the Ministry of Health and Welfare     

Phosphorylation of neurofilaments is altered in amyotrophic lateral sclerosis

We used a library of monoclonal antibodies (Mab) that distinguish phosphorylated (P+) and non-phosphorylated (P-) neurofilament (NF) epitopes to examine phosphorylation of NF in lower motor neurons of patients with amyotrophic lateral sclerosis (ALS), of neurologically normal controls of different ages, and of patients with central chromatolysis due to injuries to motor root axons. Monoclonal antibodies directed to P+ NF immunostained five to ten times more neuronal perikarya in ALS than in age-matched controls. Spheroids, which are NF containing axonal enlargements, found in significantly greater number in proximal axons in ALS, were also intensely immunostained with Mab to P+ NF. Moreover, anterior root axons in five of eleven cases of ALS reacted only with the Mab to P+ NF, while both P- and P+ NF were present in motor roots from controls. In control groups, the number of neuronal perikarya and spheroids that immunoreacted with the Mab to P+ NF increased moderately with age. Chromatolytic lower motor neurons were recognized by Mab to P+ NF. Our results show that the process of phosphorylation is altered in ALS. We propose that phosphorylation of NF in ALS occurs prematurely and that it is more likely to be associated with an impairment of NF transport than to be part of a chromatolytic reaction of lower motor neurons.     

Membranous cytoplasmic bodies in the anterior horn neurons in two patients with amyotrophic lateral sclerosis

We observed abundant membranous cytoplasmic bodies in several remaining anterior horn neurons in two patients with sporadic amyotrophic lateral sclerosis (ALS). These bodies were rare in the neurons of the frontal cortex and of the rectum examined in one case. The link between membranous cytoplasmic bodies and ALS is vague; however, pathogenesis of ALS is unknown and there are few reports on the lysosomal system in ALS. Therefore, further study is needed in order to evaluate abnormalities in the lysosomal system to clarify the degenerative processes in ALS.     

Ultrastructure of the Bunina bodies in anterior horn cells of amyotrophic lateral sclerosis

Summary Light and electron microscopic studies were made on the anterior horn cells in a case of amyotrophic lateral sclerosis. Eosinophilic inclusions of Bunina type were observed almost selectively in the motor neurons of spinal cord, as well as of brain stem, at the light microscopic level. Fine structural study revealed the presence of two types of cytoplasmic inclusions. The first, mainly corresponding to the light microscopic inclusions, were homogeneous, electron-dense, round- or oval-shaped bodies with vesicular or tubular rims and ribosome particles, about 2–5 in diameter, which contained filaments or other cytoplasmic components in the clear areas within them. The second were lamellar structures (laminated cytoplasmic bodies, Morales) which appeared to be originating from endoplasmic reticulum. There was no distinct transition in these two types of inclusions and the relationship to each other is not clear. The significance of Bunina body is unknown, but some manifestation of a primary disorder, e.g., protein metabolism, rather than a secondary degenerative change in the motor neurons in amyotorophic lateral sclerosis.     

Upregulation of protein-tyrosine nitration in the anterior horn cells of amyotrophic lateral sclerosis

Objective: Neuropathy caused by vincristine toxicity can be diagnosed by electrophysiological examination. The purpose of this study is to demonstrate the electrophysiological features of vincristine toxicity.

Methods: Electrophysiological data from 25 children receiving vincristine treatment and 25 normal controls were evaluated retrospectively. Nerve conduction study (NCS) parameters were compared. Additionally amplitude and negative peak duration (NPD) of distal compound muscle action potentials (CMAP) were analysed by factor analysis.

Results: Distal CMAP amplitudes in the patient group were significantly lower and the distal CMAP NPDs were prolonged. There were no significant differences in other motor and sensory NCS parameters.

Conclusion: Contrary to generally accepted sensorimotor involvement, motor NCS abnormalities are more pronounced in vincristine toxicity. The current study is the first time prolonged distal CMAP NPDs were detected and indicated in vincristine-related weakness, which may be a clue to understanding its mechanism, as well as differentiating from other situations.     

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.     

RET-like immunostaining of spinal motoneurons in amyotrophic lateral sclerosis

The receptor tyrosine kinase RET is part of a functional receptor for glial cell derived neurotrophic factor (GDNF) and neurturin (NTN) which are potent neurotrophic factors for motoneurons. Here, we have studied RET-like immunoreactivity of motoneurons in post-mortem spinal cords of patients with amyotrophic lateral sclerosis (ALS) and in controls. We report that the intensity of RET-like immunostaining of motoneurons in ALS is decreased significantly to 81% of control values. Despite this change, the proportion of all large (>40 μm diameter) motoneurons showing RET-like immunoreactivity in ALS remains high (82–85%) and is not significantly different to controls. The persistence of RET-like immunoreactivity in the majority of large motoneurons in ALS could be important in the design of clinical trials of GDNF and NTN.     

Expression of nitric oxide synthases in the anterior horn cells of amyotrophic lateral sclerosis

The authors investigated for a correlation between the expression of nitric oxide synthases (NOSs) with the severity of motor neuronal loss in the anterior horns of patients with amyotrophic lateral sclerosis (ALS). Spinal cords from six patients with ALS and from three normal controls were examined. The sections of cervical, lumbar, and sacral cord including Onuf's nucleus, which are seldom degenerated until the late stage, were stained with three antibodies against NOSs (anti-n-NOS, anti-e-NOS, and anti-i-NOS) using ABC methods. Perikarya of motor neurons in ALS, but not in controls, were immunoreactive against anti-n-NOS and e-NOS. Anti-i-NOS did not recognize the motor neurons of ALS or of controls. The immunoreactivity for n- and e-NOSs was approximately the same in the sections of cervical, lumbar, and sacral cord in ALS. No significant differences in immunoreactivity were observed among the patients with ALS. These results suggest that the expression of NOSs does not immediately affect neuronal loss in ALS.     

Ubiquitin-immunoreactive filamentous inclusions in anterior horn cells of Guamanian and non-Guamanian amyotrophic lateral sclerosis

Summary Immunohistochemical studies with an antibody to ubiquitin revealed the presence of filamentous inclusions in spinal anterior horn cells in all of six patients with Guamanian amyotrophic lateral sclerosis (ALS) and one of six cases of parkinsonism-dementia complex (PD) on Guam. Similar ubiquitin-reactive filamentous inclusions were found in all of seven non-Guamanian sporadic ALS patients examined. No similar inclusions were seen in six normal controls or in non-ALS patients who had chromatolytic neurons. The filamentous inclusions differed from spinal neurofibrillary tangles, a characteristic feature of Guamanian ALS and PD, since they were restricted to anterior horn cells and did not react with anti-tau antibody. The chromatolytic neurons of non-ALS patients occasionally had weak diffuse immunoreactivity, but no focal inclusions were detected. These results suggest that ubiquitin-reactive focal filamentous inclusions may reflect a characteristic degenerative process of anterior horn cells of motor neuron disease.     

Dendritic synapses of anterior horn neurons in amyotrophic lateral sclerosis: an ultrastructural study

This ultrastructural study deals with the synapses of primary dendrites of the anterior horn neurons in the lower lumbar spinal cords of seven patients with amyotrophic lateral sclerosis (ALS) who had mild neuronal depletion. Specimens from seven age-matched, neurologically normal individuals served as controls. In each instance, the autopsy was performed within 6 h after death. Our results indicate a statistically significant increase in degenerative changes in the dendrite presynapses of normal-appearing neurons of the ALS patients. The alterations included aggregation of electron-dense synaptic vesicles and dark mitochondria with dense cristae, and bundles of neurofilaments. However, we found no significant difference between controls and patients with respect to cross-sectional area and length of the dendrites, number of synapses per dendrite, and lengths of individual synapses and their active zones in the normal-appearing neurons, even though the patients' neurons had a smaller cross-sectional area. In chromatolytic neurons, the number of synapses and the length of the active zone of the primary dendrites were significantly diminished. These findings suggest that despite degenerative changes of the presynapses, the synapses in the primary dendrites of the anterior horn neurons are preserved at the early stage of ALS. The preservation of these synapses may be due to their relative resistance to degenerative processes, or may represent a compensatory mechanism of the synapses for diminished synaptic function in distal dendrites. Received: 21 July 1995 / Accepted: 6 September 1995     

Current application of neurofilaments in amyotrophic lateral sclerosis and future perspectives

Motor neuron disease includes a heterogeneous group of relentless progressive neurological disorders defined and characterized by the degeneration of motor neurons.Amyotrophic lateral sclerosis is the most common and aggressive form of motor neuron disease with no effective treatment so far.Unfortunately,diagnostic and prognostic biomarkers are lacking in clinical practice.Neurofilaments are fundamental structural components of the axons and neurofilament light chain and phosphorylated neurofilament heavy chain can be measured in both cerebrospinal fluid and serum.Neurofilament light chain and phosphorylated neurofilament heavy chain levels are elevated in amyotrophic lateral sclerosis,reflecting the extensive damage of motor neurons and axons.Hence,neurofilaments are now increasingly recognized as the most promising candidate biomarker in amyotrophic lateral sclerosis.The potential usefulness of neurofilaments regards various aspects,including diagnosis,prognosis,patient stratification in clinical trials and evaluation of treatment response.In this review paper,we review the body of literature about neurofilaments measurement in amyotrophic lateral sclerosis.We also discuss the open issues concerning the use of neurofilaments clinical practice,as no overall guideline exists to date;finally,we address the most recent evidence and future perspectives.     

Enzymatic analysis of individual anterior horn cells in amyotrophic lateral sclerosis and Duchenne muscular dystrophy

Five enzyme activities related to glucose metabolism, i.e. glucose-6-phosphate dehydrogenase (G6PDH), isocitric dehydrogenase (ICDH), citrate synthase (CS), ATP citrate lyase (ACL), and pyruvate dehydrogenase complex (PDC), were estimated in anterior horn cells (AHCs) of spinal cords in amyotrophic lateral sclerosis (ALS) and Duchenne muscular dystrophy (DMD) patients by means of the NADP and CoA cycling methods.In ALS, only CS activity was reduced significantly in AHCs, but that of posterior root ganglion cells (PRGCs) remained within the normal range.In DMD, ICDH, CS, ACL and PDC activities were within normal range. However, G6PDH activities were elevated significantly in 2 out of 3 patients examined.     

GAP-43 gene expression is increased in anterior horn cells of amyotrophic lateral sclerosis.

In amyotrophic lateral sclerosis (ALS), neuronal loss and axonal degeneration occur in motor neurons. Although there is limited axonal regeneration, surviving motor neurons send collateral sprouts to denervated muscle fibers. GAP-43, a protein enriched in growth cones and synaptic terminals, is thought to have a role in axonal elongation and synaptogenesis. GAP-43 messenger RNA (mRNA) expression was evaluated in ALS spinal cords using Northern blot analysis and in situ hybridization to assess whether surviving neurons can mount an appropriate response to injury. There was a two- to four-fold increase in GAP-43 mRNA in ALS that localized to the anterior horn cells. The increase in GAP-43 mRNA indicates that the mechanism which leads to degeneration in ALS does not compromise the neuron's capacity for vigorous expression of growth-associated proteins.     

Fine structure of anterior horns in patients without amyotrophic lateral sclerosis

Light and electron microscopic study of the anterior horns in nine patients without amyotrophic lateral sclerosis (ALS) disclosed several features usually described in ALS. Central chromatolysis and spheroids with fine structure identical to that seen in ALS were observed in three cases. Rare honeycomb-like structures, dense filamentous aggregates, dense granular deposits, stubby mitochondria and membrane-bound aggregates of spherical and tubular particles were also observed. No typical Bunina bodies or focal argyrophilia of the chromatolytic neurons were found.     

以胸髓前角先受累的肌萎缩侧索硬化的临床特点

目的探讨胸髓前角先受累的肌萎缩侧索硬化(ALS)患者的临床特征。方法回顾性分析3例以胸髓前角先受累的ALS患者的临床资料。结果3例患者均为男性,发病年龄分别为52岁、66岁、62岁;均以呼吸困难为首发表现,有明显的肋间肌和腹直肌萎缩,而肢体肌无力及肌萎缩的出现相对较轻、较迟;肌电图显示上肢及椎旁肌的神经源性损害。结论以胸髓前角先受累的ALS患者以男性多见,起病年龄晚于ALS的平均发病年龄,呼吸困难明显,呼吸肌萎缩早于肢体肌无力及肌萎缩,肌电图检查可以确诊。     

Comparative immunohistochemical study on synaptophysin expression in the anterior horn of post-poliomyelitis and sporadic amyotrophic lateral sclerosis

This report concerns a comparative study of alterations of anterior horn presynaptic terminals in post-poliomyelitis and sporadic amyotrophic lateral sclerosis (S-ALS). Synaptophysin (SP) served as a marker for presynaptic terminals; immunohistochemical techniques were used throughout. Spinal cords from six individuals without neurological disease served as controls. Localized and well-delineated anterior horn neuropil areas with decreased SP immunoreactivity were observed in the five cases of post-poliomyelitis studied. These areas had few remaining neurons but had pronounced reactive gliosis which corresponded to those areas in which typical poliomyelitis lesions were present. Normal neuronal SP expression was preserved in the adjacent, non-affected areas. However, a small region with increased SP levels was observed in one case. By comparison, the decrease in anterior horn SP immunoreactivity was diffuse in the four S-ALS patients studied. The present data suggest that presynaptic terminals ending at the somata and processes of affected anterior horn neurons located in the area of the acute infection are degenerate in post-poliomyelitis. By contrast, in S-ALS the terminals ending at distal dendrite portions tend to be severely degenerate, while those terminating at the proximal portions of the neuron are relatively well preserved. Our results thus provide additional evidence that the pathogenesis of the post-poliomyelitis state differs from that of ALS. Received: 29 August 1995 / Revised, accepted: 28 February 1996     

Spinal anterior horn has the capacity to self‐regenerate in amyotrophic lateral sclerosis model mice

The exact host environment necessary for neural regeneration in amyotrophic lateral sclerosis (ALS) has not yet been fully elucidated. We first focused on the extracellular matrix proteins in ALS model mice during development of the disease and then attempted to examine whether regeneration occurs in the ALS spinal cord under regenerative conditions. A progressive increase in γ1 laminin (a promoter of regeneration) and a progressive decrease in semaphorin3A (Sema3A; an inhibitor of regeneration) were observed, mainly in the neuropil of the spinal anterior horn from 15 to 18 weeks, when astrocytes began to express both γ1 laminin and Sema3A. On the other hand, a progressive increase in growth‐associated protein 43 (GAP43; synaptic regeneration site) and a progressive decrease in synaptotagmin1 (actual synaptic bouton) were observed in the same areas of the spinal anterior horn from 15 to 18 weeks. Thus, the present data suggest that, although the spinal anterior horn in ALS models loses motor neurons, it initially possesses the capacity to self‐regenerate but displays a progressive loss of ability to regenerate new effective synapses. © 2009 Wiley‐Liss, Inc.