Protective effect of interleukin-3 and erythropoietin on motor neuron death after neonatal axotomy

Several members of hematopoietic factors are known to have neuroprotective effects against axotomized motor neuron death. We carried out a study to determine whether interleukin-3 (IL-3) and erythropoietin (EPO) rescue spinal motor neuron death following axotomy. Unilateral sciatic nerve was transected in neonatal rats. Different doses of IL-3, EPO, or vehicle were administered daily for two weeks by intraperitoneal injection. After treatment, the number of spinal motor neurons was determined at the level of L4 segment In comparison with vehicle, both IL-3 (10 microg kg(-1)) and EPO (5.0 mg kg(-1)) significantly prevented the loss of motor neurons. Protective potentials is the same between them. These results suggest that IL-3 and EPO play a role for motor neuron survival in vivo and suggest the potential use of these hematopoietic factors in treating diseases that involve degeneration and death of motor neurons, such as motor neuropathy and amyotrophic lateral sclerosis.

Impairment of the peripheral nervous system in Creutzfeldt-Jakob disease

BACKGROUND

The clinical manifestations of Creutzfeldt-Jakob disease (CJD) primarily reflect involvement of the central nervous system. The coexistence of CJD with peripheral nervous system involvement has also been reported.

OBJECTIVE

To analyze peripheral neuron electrophysiologic changes and to compare these data with neuropathologic features of spinal motor neurons in patients with definite CJD.

DESIGN AND PATIENTS

Electrophysiologic examinations were performed on 16 patients with sporadic CJD. The diagnosis was confirmed by neuropathologic examinations (15 patients) or by intravital detection of the 14-3-3 protein in the cerebrospinal fluid (1 patient). The spinal cord was neuropathologically examined in 8 patients.

SETTING

Department of Clinical Neurophysiology, I Neurological Department, Institute of Psychiatry and Neurology, Warsaw, Poland.

MAIN OUTCOME MEASURES

Electromyography, compound muscle and sensory nerve action potentials, distal latencies, F waves, peripheral motor and sensory conduction velocity, and spinal motor neuron numbers and morphologic characteristics.

RESULTS

All patients had signs of central nervous system damage typical of sporadic CJD. Only 3 patients had clinical signs of peripheral nervous system involvement. Electrophysiologic examinations confirmed peripheral nervous system damage in these patients and revealed preclinical peripheral nervous system impairment in 11 more patients. In 1 patient, electrophysiologic examination revealed features of motor neuron disease; in 9, axonal disease; and in 4, axonal-demyelinating neuropathy. Neuropathologic examination results confirmed severe loss of spinal motor neurons in 1 patient with motor neuron disease and revealed the features of motor neuron chronic disease in 4. In 2 of them, electrophysiologic data were normal.

CONCLUSION

In sporadic cases of CJD, peripheral nervous system impairment should be considered to be an integral component of disease.

Trophic effect of olmesartan, a novel AT1R antagonist, on spinal motor neurons in vitro and in vivo

Olmesartan is a novel compound which has been shown to exhibit various neuropharmacological effects. For the purpose of clarifying the effect of Olmesartan on spinal motor neurons, we studied the following tests. We studied the effect in vitro of Olmesartan on neurite outgrowth and choline acetyltransferase (ChAT) activity in primary explant cultures of ventral spinal cord (VSCC) of fetal rats. Olmesartan-treated VSCC, compared with control VSCC, had a significant neurite outgrowth and increased activity of ChAT. The effect was dose-related in neurite outgrowth. However, there was no relationship between activity of ChAT andgiven doses of Olmesartan. We examined in vivo the effect of Olmesartan on axotomized spinal motor neuron death in the rat spinal cord. After post-natal unilateral section of sciatic nerve, there was approximately a 50% survival of motor neurons in the fourth lumbar segment. In comparison with vehicle, intraperitoneal injection of Olmesartan for consecutive 14 days reduced spinal motor neuron death. There was no relationship between number of surviving neurons and doses of Olmesartan. These in vitro and in vivo studies showed that Olmesartan has a neurotrophic effect on spinal motor neurons. Our data suggest a potential therapeutic use of Olmesartan in treating diseases that involve degeneration and death of motor neurons, such as motor neuropathy and amyotrophic lateral sclerosis.

Neuronal death is enhanced and begins during foetal development in type I spinal muscular atrophy spinal cord

Spinal muscular atrophy (SMA) is an autosomal recessive disorder caused by mutations in the survival motor neurone gene (SMN). The degeneration and loss of the anterior horn cells is the major neuropathological finding in SMA, but the mechanism and timing of this abnormal motor neurone death remain unknown. A quantitative study was carried out comparing neuronal death in controls and SMA foetuses and neonates. Between 12 and 15 weeks of gestational age, a significant increase in nuclear DNA vulnerability, as revealed with the method of in situ end-labelling of nuclear DNA fragmentation, was detected in SMA foetuses and was reflected by a decrease in the number of neurones of the anterior horn. Neurones with nuclear DNA vulnerability are no longer detected at the end of the foetal period and the post-natal period. On the other hand, abnormal morphology of motor neurones, mainly early chromatolytic changes, was observed only after birth. Our findings indicate that in type I SMA, the absence or dysfunction of SMN is reflected by an enhanced neuronal death that is already detectable at 12 weeks, the earliest SMA foetal stage analysed. This is associated with a progressive loss of motor neurones towards the neonatal period. Given that a proportion of the remaining SMA motor neurones in the neonatal period appear with pathological findings not detected at earlier stages, it can be hypothesized that type I SMA results in differential age-dependent responses leading to cell death and motor neurone degeneration during development.

DL-Homocysteic acid application disrupts calcium homeostasis and induces degeneration of spinal motor neurons in vivo

Excitotoxicity, autoimmunity and free radicals have been postulated to play a role in the pathomechanism of amyotrophic lateral sclerosis (ALS), the most frequent motor neuron disease. Altered calcium homeostasis has already been demonstrated in Cu/Zn superoxide dismutase transgenic animals, suggesting a role for free radicals in the pathogenesis of ALS, and in passive transfer experiments, modeling autoimmunity. These findings also suggested that yet-confined pathogenic insults, associated with ALS, could trigger the disruption of calcium homeostasis of motor neurons. To test the possibility that excitotoxic processes may also be able to increase calcium in motor neurons, we applied the glutamate analogue DL-homocysteic acid to the spinal cord of rats in vivo and analyzed the calcium distribution of the motor neurons over a 24-h survival period by electron microscopy. Initially, an elevated cytoplasmic calcium level, with no morphological sign of degeneration, was noticed. Later, increasing calcium accumulation was seen in different cellular compartments with characteristic features of alteration at different survival times. This calcium accumulation in organelles was paralleled by their progressive degeneration, which culminated in cell death by the end of the observation time. These findings confirm that increased calcium also plays a role in excitotoxic lesion of motor neurons, in line with previous studies documenting the involvement of calcium ions in motor neuronal injury in other models of the disease as well as elevated calcium in biopsy samples from ALS patients. We suggest that intracellular calcium might be responsible for the interplay between the different pathogenic processes resulting in a uniform clinicopathological picture of the disease.

Neuronal nitric oxide synthase (nNOS) immunoreactivity in the spinal cord of transgenic mice with G93A mutant SOD1 gene

Immunohistochemical and quantitative analyses were used to examine the evolution of neuronal nitric oxide synthase (nNOS) with time in spinal motor neurons of transgenic mice with a G93A mutant Cu/Zn superoxide dismutase (SOD1) gene. Specimens from age-matched non-transgenic wild-type mice served as controls. In the controls, the anterior horn including the anterior horn neurons was not immunostained for nNOS. In the transgenic mice, at the age of 24 weeks (early presymptomatic), when no pathological change was observed in the spinal cord, anterior horn neurons were only occasionally immunostained for nNOS (0.3%). At the age of 28 weeks (late presymptomatic), nNOS-positive anterior horn neurons and their neuronal processes were occasionally observed (7.6%), and at the age of 32 weeks (early symptomatic), nNOS-positive anterior horn cells, including degenerated ones showing central chromatolysis, were frequently demonstrated (27.6%) and nNOS-positive cord-like swollen proximal axons were also observed in the anterior horns. nNOS expression in the anterior horn neurons was almost always observed in the somata. At the age of 35 weeks (end stage), neuronal loss of the anterior horn cells was severe, and nNOS-positive anterior horn neurons and cord-like swollen axons in the anterior horns were less prominent compared to those at the age of 32 weeks (33.8%), but many reactive astrocytes were immunostained for nNOS. Thus, nNOS immunoreactivity in the anterior horn neurons is observed as early as the presymptomatic stage and varies with the progression of the disease. The selective localization of positive nNOS immunoreactivity in the anterior horn neurons and degenerated ones in particular, and swollen proximal axons suggests that nNOS immunoreactivity may be involved in the degeneration of anterior horn neurons in this SOD1 transgenic mouse model.

Longitudinal study of functional spinal alpha motor neuron loss in amyotrophic lateral sclerosis

Using a microstimulation technique for obtaining motor unit number estimates (MUNEs) of the hypothenar and extensor digitorum brevis (EDB) muscles, we performed a longitudinal study on the natural course of change in the clinical rating scale (Appel score) and of loss of functional spinal alpha motor neurons in amyotrophic lateral sclerosis. The Appel score increased to about 150% of normal at 12 months after onset, about 225% at 18 months after onset, and about 370% at 24 months after onset. By contrast, MUNEs decreased to about 27% of normal at 12 months after onset, about 12% at 18 months after onset, and about 5% at 24 months after onset. The relative merits of these different approaches in detecting changes in the disease process in its early phase are discussed.

Electrophysiological evaluation of conduction in the most proximal motor root segment

Root conduction time (RCT), defined as the time difference between M-wave latency by cervical magnetic stimulation (CMS) and the total peripheral motor conduction time calculated from the shortest F-wave latency, was investigated in patients with inflammatory demyelinating neuropathies (IDP) and amyotrophic lateral sclerosis (ALS). The minimal threshold for CMS also was studied. In the IDP patients, conduction in the proximal motor root segment was considered abnormal in 52% by the RCT and in 47% by the minimal threshold for CMS, whereas both were normal in 85% of the ALS patients. These findings suggest that the RCT and minimal threshold for CMS might be additional parameters for evaluating motor nerve conduction in IDP.

Positive effect of transplantation of hNT neurons (NTera 2/D1 cell-line) in a model of familial amyotrophic lateral sclerosis

Transplantation of hNT Neurons derived from the human teratocarcinoma cell-line (NTera2/D1) has been shown to ameliorate motor dysfunction in a number of injury or disease models in which the deficits are fairly localized. However, these cells have not been used before in a model with more extensive neurodegeneration. The aim of this study is to determine the effects of hNT Neuron transplants on motor neuron function in a mouse model of familial amyotrophic lateral sclerosis (FALS) in which there is a substitution of Alanine for Glycine at position 93 of the human SOD1 gene (G93A). Amyotrophic lateral sclerosis is a fatal degenerative motor neuron disease affecting the spinal cord, brainstem, and cortex. This disease clinically manifests as progressive muscular weakness and atrophy, leading to paralysis and death within 3-5 years of diagnosis. The FALS represents 10-13% of all cases. A range of behavioral tests was used to examine spontaneous locomotor activity, coordination, and muscle strength of mice. Long-term (10-11 weeks) transplantation of hNT Neurons into the L(4)-L(5) segments of the ventral horn spinal cord of FALS(G93A) mice at 7 weeks of age (before onset of overt behavioral symptoms of disease) delayed the onset of motor dysfunction for at least 3 weeks. The average lifespan of the transplanted mice was 128 days compared to 106 days for media-injected group. The last mouse in the hNT Neuron transplanted group was euthanized at 135 days of age when it display partial paralysis of the hindlimbs. Immunohistochemical analysis of the implanted spinal cords demonstrated the survival of grafted hNT Neurons and showed many healthy-appearing motor neurons near the implant site. These results suggest that hNT Neuron transplantation may be a promising therapeutic strategy for ALS.

The Golgi apparatus is fragmented in spinal cord motor neurons of amyotrophic lateral sclerosis with basophilic inclusions

The mechanisms of neuronal death in amyotrophic lateral sclerosis (ALS) are not known. A pathological aggregation of cytoplasmic constituents in the form of variety of inclusions may play a role in the pathogenesis of neuronal death. Cytoplasmic basophilic inclusions (BIs) in motor neurons are commonly found in sporadic juvenile ALS. The functional significance of these inclusions is not known, i.e., whether they represent a protective reaction for the isolation of abnormal products from the cytoplasm, or a sign of irreversible neuronal damage. To gain insights on the significance of BIs we asked whether neurons with BIs had an intact or fragmented Golgi apparatus (GA), a sign of neuronal degeneration reported not only in sporadic and familial ALS with mutations of the Cu/Zn superoxide dismutase gene (SOD1), but also in transgenic mice expressing the G93A mutation of SOD1. In these mice fragmentation of the GA of spinal cord motor neurons was found months before the onset of paralysis. We report here that all neurons bearing the inclusions showed fragmentation and reduced number of GA. These results suggest that common pathogenetic mechanisms are involved in the production of BIs and in the fragmentation of the GA.

Differential expression between synaptic vesicle proteins and presynaptic plasma membrane proteins in the anterior horn of amyotrophic lateral sclerosis

This study concerns the immunohistochemical investigation of synaptic proteins in the anterior horn of amyotrophic lateral sclerosis (ALS). Antibodies against synapsin 1 and synaptophysin (i.e. synaptic vesicle proteins), and those against syntaxin and the synaptosomal-associated, 25 kDa protein, SNAP25 (i.e. presynaptic plasma membrane proteins) were used for immunostaining, respectively. Lumbar spinal cords from five ALS and eight control patients were examined. In the controls, all four synaptic proteins exhibited fine granular immunoreactivities, distributed throughout the spinal gray matter almost uniformly. In contrast, in all five ALS patients, two of the synaptic vesicle proteins examined decreased in the anterior horn neuropil diffusely, while in the same lumbar segments of these cases the immunoreactivities of the two presynaptic plasma membrane proteins showed no apparent decrease, or were only mildly diminished in the same gray matter area. These results indicate that, during the presynaptic terminal degeneration in the anterior horn of ALS, synaptic vesicle involvement may precede that of the presynaptic plasma membrane.

Peri-ischemic aminoguanidine fails to ameliorate neurologic and histopathologic outcome after transient spinal cord ischemia

Inhibition of neurotoxic events that lead to delayed cellular damage may prevent motor function loss after transient spinal cord ischemia. An important effect of the neuroprotective substance aminoguanidine (AG) is the inhibition of inducible nitric oxide synthase (iNOS), a perpetrator of focal ischemic damage. The authors studied the protective effects of AG on hind limb motor function and histopathologic outcome in an experimental model for spinal cord ischemia, and related these findings to the protein content of iNOS in the spinal cord. Temporary spinal cord ischemia was induced by 28 minutes of infrarenal balloon occlusion of the aorta in 40 anesthetized New Zealand White rabbits. Animals were assigned randomly to two treatments: saline (n = 20) or AG (n = 20; 100 mg/kg intravenously before occlusion). Postoperatively, treatment was continued with subcutaneous injections twice daily (saline or 100 mg/kg AG). Normothermia (38 degrees C) was maintained during ischemia, and rectal temperature was assessed before and after subcutaneous injections. Animals were observed for 96 hours for neurologic evaluation (Tarlov score), and the lumbosacral spinal cord was examined for ischemic damage after perfusion and fixation. Lastly, iNOS protein content was determined using Western blot analysis 48 hours after ischemia in five animals from each group. Neurologic outcome at 96 hours after reperfusion was the same in both groups. The incidence of paraplegia was 67% in the saline-treated group versus 53% in the AG-treated group. No differences in infarction volume, total number of viable motoneurons, or total number of eosinophilic neurons were present between the groups. At 48 hours after reperfusion, iNOS protein content in the spinal cord was increased in one animal in the AG-treated group and in three animals in the control group. The data indicate that peri-ischemic treatment with high-dose AG in rabbits offers no protection against a period of normothermic spinal cord ischemia. There was no conclusive evidence of spinal cord iNOS inhibition after treatment with AG.

Acidic fibroblast growth factor (FGF-1) in the anterior horn cells of ALS and control cases

The expression and localization of acidic fibroblast growth factor (aFGF; FGF-1) were examined in the spinal cord of patients with amyotrophic lateral sclerosis (ALS) and controls by reverse transcription-polymerase chain reaction (RT-PCR) method and immunohistochemistry. The RT-PCR experiments demonstrated that aFGF amplification products were clearly detected in all control cases but could be scarcely seen in ALS patients. aFGF immunoreactivity was detected in the anterior horn cells of the spinal cord. Double immunostaining for aFGF and choline acetyltransferase revealed that the majority (95.9%) of cholinergic neurons expressed aFGF. In ALS cases, the number and the staining intensity of aFGF-positive neurons were markedly decreased. These results suggest that aFGF is involved in ALS pathology.

Intraspinal implantation of hNT neurons into SOD1 mice with apparent motor deficit

INTRODUCTION

The aim of this study was to determine the effect of hNT neuron transplants on motor neuron function in SOD1 (G93A) mice when motor deficits were already apparent.

METHOD

The hNT neurons were implanted into L(4)-L(5) segments of the ventral horn spinal cord of mice at 15-16 weeks of age: either G93A mice, transgenic mice carrying the normal allele for human SOD1 gene (hTg), or control wild type mice (wt). Behavioral tests (rotorod, beam balance, extension reflex, footprint) were performed prior to transplantation and at weekly intervals afterwards.

RESULTS

HNT neuron transplantation in the SOD1 mice delayed disease progression for 3-4 weeks, although lifespan was not affected.

CONCLUSION

These results suggest that hNT neuron transplantation may be a promising therapeutic strategy for ALS in the later phase of the neurodegeneration.

A clinical and pathological study of motor neurone disease on Guam

Despite over 40 years of intensive study, the cause of the high incidence of motor neurone disease (MND) on Guam, and the relationship between this disease and MND seen in the rest of the world are still uncertain. We present a series of 45 cases of Guamanian MND, which reaffirm the clinical similarity between this disease and MND seen in other countries. However, the occurrence of MND among the indigenous Chamorros of Guam is distinguished by four factors: (i) high prevalence; (ii) frequent familial occurrence; (iii) co-occurrence with the parkinsonism-dementia complex (PDC); and (iv) association with an unusual and distinctive linear retinopathy termed Guam retinal pigment epitheliopathy (GRPE). These distinguishing factors were not present in four non-Chamorros who resided on Guam when their MND symptoms occurred. Pathologically, the classical features of MND were seen in Guamanian Chamorro cases including ubiquitin inclusions. Neurofibrillary tangles were frequently seen. The neurofibrillary tangles appeared in the same distribution as described in the PDC but, unlike classical PDC, they were not usually associated with cell loss and occurred less frequently. While neurofibrillary tangle formation and the clinicopathological syndrome of MND may occur in parallel, observations from this series suggest that pathologically classical MND on Guam may occur independently of neurofibrillary degeneration and the clinical features of PDC.

Immune reactivity in a mouse model of familial ALS correlates with disease progression

OBJECTIVE

The cause of motor neuron death in ALS is incompletely understood. This study aims to define the potential involvement of nonneuronal immune-inflammatory factors in the destruction of motor neurons in mutant superoxide dismutase-1 (SOD1) transgenic mice as a model of ALS.

BACKGROUND

The presence of activated microglia, IgG and its receptor for Fc portion (FcgammaRI), and T lymphocytes in the spinal cord of both patients with ALS and experimental animal models of motor neuron disease strongly suggests that immune-inflammatory factors may be actively involved in the disease process.

METHODS

The expression of immune-inflammatory factors was followed in both human mutant (G93A) SOD1 transgenic mice and human wild-type SOD1 transgenic mice, at different ages (40, 80, and 120 days). Fixed, frozen, free-floating sections of the lumbar spinal cord were stained with antibodies against CD11b, IgG, FcgammaRI, intercellular adhesion molecule-1 (ICAM-1), CD3, and glial fibrillary acidic protein.

RESULTS

The earliest change observed was the upregulation of ICAM-1 in the ventral lumbar spinal cord of 40-day-old mutant SOD1 mice. IgG and FcgammaRI reactivities were detected on motor neurons as early as 40 days and on microglial cells at later stages. Microglial activation was first evident in the ventral horn at 80 days, whereas reactive astrocytes and T cells became most prominent in 120-day-old mutant SOD1 mice.

CONCLUSION

The upregulation of proinflammatory factors during early presymptomatic stages as well as the expansion of immune activation as disease progresses in mutant SOD1 transgenic mice suggest that immune-inflammatory mechanisms could contribute to disease progression.

Ubiquitin immunoreactivity in presumed spinal interneurones in motor neurone disease

Previous studies have demonstrated the presence of ubiquitin-immunoreactivity (Ub-IR) as inclusions and skeins in motor neurones of both the familial and sporadic forms of motor neurone disease (MND). There is evidence that interneurones also degenerate in MND, but Ub-IR in ventral horn spinal interneurones has not been studied previously. Here, Ub-IR was investigated in 1445 presumed interneurones and 1086 presumed motor neurones counted in three random 20-microm sections of the ventral horn of the third lumbar segment of the spinal cord of each of seven controls and seven patients with MND. The ventral horn was divided into four quadrants; the dorsomedial quadrant contains almost exclusively interneurones and the ventrolateral quadrant largely motor neurones. The neurones were also classified by morphological and size criteria into presumed interneurones (< 25 microm) and presumed motor neurones (>or= 25 microm). Ub-IR was classified as inclusions, skeins and dispersed cytoplasmic and nuclear staining. Ub-IR inclusions or skeins were not observed in the controls but 6.6% of neurones (motor neurones and interneurones) showed the presence of dispersed cytoplasm staining and nuclear staining. The incidence of Ub-IR cytoplasmic and nuclear staining was significantly greater in both motor neurones and interneurones of MND patients than controls. Ub-IR was less frequent in MND cases in which a great loss of neurones was observed. Ub-IR was significantly more frequent in motor neurones than interneurones, both in patients and controls. Ub-IR inclusions and skeins were only observed in motor neurones from MND patients. Ub-IR inclusions were not observed in presumed spinal interneurones, while skeins were only seen in three out of 565 of these cells (two of them in the dorsomedial quadrant) in two out of seven patients. Thus, although presumed spinal interneurones occasionally revealed Ub-IR features similar to motor neurones, the rare staining of Ub-IR skeins and the lack of Ub-IR inclusions in interneurones in MND suggests that these neurones only occasionally form ubiquitin-protein conjugates. Neuronal size, rather than type, may be important in determining whether ubiquitin-protein conjugates form in the ventral horn neurones in MND.

Molecular analysis of SMN, NAIP and P44 genes of SMA patients and their families

Mutations of the telomeric survival motor neuron gene (SMN1) are related to spinal muscular atrophy (SMA). However, no phenotype-genotype correlation has been observed since the SMN1 gene is lacking in the majority of patients affected with either the severe form (type I) or the milder forms (types II and III). Here, we analyze the SMN, NAIP and P44 genes in 132 Chinese SMA patients and their families. At least three types of normal allele, and four types of mutant allele were found in this study. The combination of one normal allele with one mutant allele resulted in carriers of different types, and the combination of different mutant alleles accounted for the different genotypes among different types of SMA. Deletions of mutant alleles can be further subgrouped into four types, which includes involving SMN1, SMN1 and NAIP(T) (telomeric portion of NAIP gene), SMN1 and NAIP(T) and P44(T) (telomeric portion of P44 gene), and SMN1 and SMN2 (centromeric portion of SMN gene). Some of the severe (type I) SMA cases correlated with the extent of deletions in the SMN, NAIP and P44 genes or the dosage of SMN gene when both SMN1 and SMN2 are deleted. We also found two novel point mutations, an A insertion at codon 8 (AGT-->AAGT) and an A substitution at codon 228 (TTA-->TAA).

Preserved phosphorylation of RET receptor protein in spinal motor neurons of patients with amyotrophic lateral sclerosis: an immunohistochemical study by a phosphorylation-specific antibody at tyrosine 1062

Ret oncoprotein is a functional receptor for the glial cell line-derived neurotrophic factor (GDNF) family and it is expressed in motor neurons, playing an important role in the motor neuron function. In this study, we examined the expression of the phosphorylation state of tyrosine residue 1062 (Tyr-1062) of Ret in the spinal cords of amyotrophic lateral sclerosis (ALS), using the phosphorylation state specific antibody at Tyr-1062 of Ret. The immunohistochemical study demonstrated that Tyr-1062 of Ret was phosphorylated to variable extents in the surviving motor neurons of all the ALS as well as controls studied. This is the first report that the phosphorylation of Tyr-1062 occurred in neurons with nononcogenic type of Ret. The Ret-signaling pathway by Tyr-1062 autophosphorylation is constitutively activated via the phosphatidylinositol 3-kinase and/or mitogen-activated protein kinase cascade for motoneuron survival even in the ALS motor neurons, supporting the view that GDNF is a candidate for therapeutic approach to ALS.

Immunohistochemical and ultrastructural study of basophilic inclusions in adult-onset motor neuron disease

We immunohistochemically and ultrastructurally studied basophilic inclusions (BI) in a patient with adult-onset sporadic motor neuron disease (MND). BI were frequently observed not only in degenerated anterior horn cells, such as central chromatolytic neurons, but also in normal-appearing large anterior horn neurons. They had various shapes, round, elliptical or irregular, and occasionally they had distinct basophilic rims. They also varied in size. There were no halos around them nor core in their centers. Immunohistochemically, some BI were immunostained for ubiquitin or SOD1, but BI were not immunoreactive with anti-phosphorylated neurofilament (SMI 31), phosphorylated tau, cystatin C or Golgi (MG-160) antibodies. Ubiquitin-positive skein-like inclusions (SI) were occasionally observed in the somata of anterior horn neurons. Ultrastructurally, BI consisted of filamentous structures associated with granules, which were attached to thick filaments. The thick filaments were straight without constriction or side arms and their diameter was twice that of the neurofilaments. BI occasionally contained tubular structures among the granule-associated filaments. The granulo-filamentous profiles varied from being compactly arranged to being more loosely packed. The structure of BI resembles that of the Lewy body-like hyaline inclusions (LBHI) observed in sporadic MND patients. Bundles of filaments resembling SI, which were composed of compactly packed filaments without fine granules running parallel to the longitudinal axis, were frequently observed inside or at the periphery of BI, and occasionally clustered in the perikarya. Each filament measured approximately 15-25 nm in diameter, and a bundle of these grouped filaments was sometimes surrounded by a unit membrane. We also occasionally observed in-between structures of BI and bundles of filaments resembling SI. These findings suggest a certain relationship between BI, SI and LBHI in the pathomechanism of BI development. Further studies are needed to elucidate whether sporadic adult-onset MND characterized by BI forms a different subtype of MND.

Modulation of HSP25 expression during anterior horn motor neuron degeneration in the paralysé mouse mutant

The paralysé spontaneous mutation in mice involves degeneration and death of anterior horn motor neurons. Mutant mice are not viable past postnatal day 16. At present, the mechanisms involved in motor neuron death are unknown. Here, we investigate the expression of the small heat shock protein Hsp25, in the spinal cord of paralysé at two different stages during postnatal development, i.e., day 11 and day 14. Western blot analysis reveals that the level of Hsp25 was strikingly different in paralysé as compared to control littermates. Hsp25 expression level in paralysé at day 11 was much lower than in control mice. At day 14, an opposite pattern was observed. Such pattern seems to be restricted to spinal cord, since level of Hsp25 in other tissues (lung, brain, liver, and heart) was quite similar. Immunofluorescence examination of the lumbar spinal cord sections reveals that in control mice, Hsp25 was expressed at high level in motor neurons located in the ventral horn at both day 11 and day 14. By contrast, in paralysé mice, Hsp25 staining within the motor neurons was barely detectable except as a spot in the nucleolus (day 11). At the end stage of the disease (day 14), not only was Hsp25 staining even less intense in motor neurons, but also a strong Hsp25 staining was observed in reactive astrocytes within the gray matter. Taken together, these data suggest that Hsp25 expression is differently modulated in neuronal and glial cells during neurodegenerative processes leading to motor neuron death.

Distribution of Serotonin 2A and 2C Receptor mRNA Expression in the Cervical Ventral Horn and Phrenic Motoneurons Following Spinal Cord Hemisection

Cervical spinal cord injury leads to a disruption of bulbospinal innervation from medullary respiratory centers to phrenic motoneurons. Animal models utilizing cervical hemisection result in inhibition of ipsilateral phrenic nerve activity, leading to paralysis of the hemidiaphragm. We have previously demonstrated a role for serotonin (5-HT) as one potential modulator of respiratory recovery following cervical hemisection, a mechanism that likely occurs via 5-HT2A and/or 5-HT2C receptors. The present study was designed to specifically examine if 5-HT2A and/or 5-HT2C receptors are colocalized with phrenic motoneurons in both intact and spinal-hemisected rats. Adult female rats (250-350 g; n = 6 per group) received a left cervical (C2) hemisection and were injected with the fluorescent retrograde neuronal tracer Fluorogold into the left hemidiaphragm. Twenty-four hours later, animals were killed and spinal cords processed for in situ hybridization and immunohistochemistry. Using (35)S-labeled cRNA probes, cervical spinal cords were probed for 5-HT2A and 5-HT2C receptor mRNA expression and double-labeled using an antibody to Fluorogold to detect phrenic motoneurons. Expression of both 5-HT2A and 5-HT2C receptor mRNA was detected in motoneurons of the cervical ventral horn. Despite positive expression of both 5-HT2A and 5-HT2C receptor mRNA-hybridization signal over phrenic motoneurons, only 5-HT2A silver grains achieved a signal-to-noise ratio representative of colocalization. 5-HT2A mRNA levels in identified phrenic motoneurons were not significantly altered following cervical hemisection compared to sham-operated controls. Selective colocalization of 5-HT2A receptor mRNA with phrenic motoneurons may have implications for recently observed 5-HT2A receptor-mediated regulation of respiratory activity and/or recovery in both intact and injury-compromised states.

Inflammatory polyradiculoneuropathy with spinal cord involvement and lethal [correction of letal] outcome after hepatitis B vaccination

We report on a 36-year-old man who developed an inflammatory polyradiculoneuropathy similar to Guillain-Barré syndrome 9 days after hepatitis B vaccination. Extensive immunotherapy including immunoglobulins, steroids, plasmapheresis, cyclophosphamide and methotrexate did not stop the progressive course of the disease and the patient died 4 months later due to multiorgan failure with septic shock symptoms and adult respiratory distress syndrome (ARDS).The neuropathological investigation showed severe axonal loss with mild demyelination of peripheral nerves and mononuclear cell infiltrates, predominantly T-lymphocytes, in nerve roots and spinal ganglia. In addition, there were unusual, perivascular and parenchymal lymphocytic cell infiltrates in the grey matter, especially the anterior horns of the spinal cord. The temporal relationship to hepatitis B vaccination, the strong increase of HBs-antibodies within 3 weeks after vaccination, and the presumptive immune mediated pathology of this disorder suggest a possible etiologic link with hepatitis B vaccine.

Neuronal nitric oxide synthase immunoreactivity in the spinal cord in amyotrophic lateral sclerosis

We investigated the spinal cords of 15 patients with sporadic amyotrophic lateral sclerosis (ALS) immunohistochemically using an anti-human neuronal nitric oxide synthase (nNOS) antibody to examine whether there is increased nNOS immunoreactivity in anterior horn neurons. Specimens from 16 patients without any neurological disease served as controls. In the controls, nNOS immunoreactivity of large anterior horn neurons was detected in 10 out of 16 cases. However, there were few nNOS-positive neurons, and most of large anterior horn neurons were spared. In the ALS patients, the mean number of nNOS-positive anterior horn neurons per transverse section of L4 and L5 was significantly larger (16.2 +/- 10.9) than that in the controls (7.0 +/- 9.2) (P < 0.0001). Moreover, 41.4% of large anterior horn neurons in ALS showed nNOS immunoreactivity in remarkable contrast to 7.6% in the controls. All ALS patients, whether showing mild, moderate or severe depletion of anterior horn neurons, displayed a higher percentage of nNOS-positive anterior horn neurons than the control patients showing nNOS immunoreactivity (P < 0.01). Most of the remaining anterior horn neurons in ALS showed more intense nNOS immunoreactivity on the surface of the neurons and their neuronal processes compared with the controls. Degenerated anterior horn neurons frequently demonstrated more intense nNOS immunoreactivity on the surface of the neurons than normal-appearing neurons. Some anterior horn cells displayed nNOS immunoreactivity in the somata. Dot-like nNOS deposits on anterior horn neurons were also positively immunoreactive with anti-synaptophysin antibody. Thus, increased nNOS expression is located mainly at the synaptic sites on the anterior horn neurons in sporadic ALS, which may be related to the degeneration of anterior horn neurons in this disease. Further studies are needed to determine whether the increased nNOS immunoreactivity plays a neuroprotective or neurotoxic role in the anterior horn neurons, and to show nitric oxide production in ALS.

Temporal-spatial pattern of acute neuronal and glial loss after spinal cord contusion

The secondary loss of neurons and glia over the first 24 h after spinal cord injury (SCI) contributes to the permanent functional deficits that are the unfortunate consequence of SCI. The progression of this acute secondary cell death in specific neuronal and glial populations has not previously been investigated in a quantitative manner. We used a well-characterized model of SCI to analyze the loss of ventral motoneurons (VMN) and ventral funicular astrocytes and oligodendrocytes at 15 min and 4, 8, and 24 h after an incomplete midthoracic contusion injury in the rat. We found that both the length of lesion and the length of spinal cord devoid of VMN increased in a time-dependent manner. The extent of VMN loss at specified distances rostral and caudal to the injury epicenter progressed symmetrically with time. Neuronal loss was accompanied by a loss of glial cells in ventral white matter that was significant at the epicenter by 4 h after injury. Oligodendrocyte loss followed the same temporal pattern as that of VMN while astrocyte loss was delayed. This information on the temporal-spatial pattern of cell loss can be used to investigate mechanisms involved in secondary injury of neurons and glia after SCI.