MR neurography for the evaluation of CIDP.

INTRODUCTION: To visualize peripheral nerves in patients with chronic inflammatory demyelinating polyneuropathy (CIDP), we used MR imaging. We also quantified the volumes of the brachial and lumbar plexus and their nerve roots. METHODS: Thirteen patients with CIDP and 12 healthy volunteers were enrolled. Whole-body MR neurography based on diffusion-weighted whole-body imaging with background body signal suppression (DWIBS) was performed. Peripheral nerve volumes were calculated from serial axial MR images. RESULTS: The peripheral nervous system was visualized with 3-dimensional reconstruction. Volumes ranged from 8.7 to 49.5 cm3 /m2 in the brachial plexus and nerve roots and from 10.2 to 53.5 cm3 /m2 in the lumbar plexus and nerve roots. Patients with CIDP had significantly larger volumes than controls (P < 0.05), and volume was positively correlated with disease duration. CONCLUSIONS: MR neurography and the measurement of peripheral nerve volume are useful for diagnosing and assessing CIDP. Muscle Nerve 55: 483-489, 2017.

Differentiation of cancer from atrial fibrillation in patients with acute multifocal stroke.

OBJECTIVE: Acute multifocal embolic infarction (AMEI) is conventionally caused by etiologies such as cardioembolism due to atrial fibrillation (Af), but can also be caused by serious underlying diseases such as cancer. We characterized cancer-related AMEI and identified useful indicators for cancer-associated strokes. METHODS: A retrospective analysis was performed on 35 patients with Af-related AMEI and 35 patients with cancer-related AMEI selected from 1235 consecutive patients with acute infarcts. All patients received diffusion-weighted magnetic resonance (MR) imaging. Cerebral MR angiography, carotid and cardiac ultrasonography, electrocardiogram-monitoring and whole body computed tomography were also performed on these patients. D-dimer levels were evaluated on admission, and were measured during the sub-acute phase in 19 of the patients with Af and 27 of the patients with cancer. RESULTS: Acute phase D-dimer levels were significantly higher in patients with cancer than in patients with Af alone. The cut-off D-dimer value to identify cancer-associated infarcts was 2.0µg/mL. D-dimer levels during the sub-acute phase remained elevated in the cancer patients. CONCLUSIONS: We may differentiate cancer-associated AMEI from Af using a D-dimer level≥2.0µg/mL, which does not decrease during the sub-acute phase.

Phase II Trial of Intravenous Low-Dose Granulocyte Colony-Stimulating Factor in Acute Ischemic Stroke.

BACKGROUND: Granulocyte colony-stimulating factor (G-CSF) has shown neuroprotective and neurogenerative activities in experimental studies, and our previous phase I clinical study suggested the safety and potential efficacy of low-dose G-CSF in acute ischemic stroke patients. The present phase II trial is aimed to evaluate the effect of G-CSF administration on neurological function and infarct volume, compared with a placebo group. METHODS: Forty-nine acute ischemic stroke patients (29 males, 20 females; 71 ± 10 years) within 24 hours after onset were recruited. Eligible patients were randomized 2:2:1 to receive G-CSF 150 µg/body/day, G-CSF 300 µg/body/day, and placebo, respectively. We evaluated clinical outcome in terms of the National Institutes of Health Stroke Scale, the modified Rankin Scale, and the Barthel Index at 90 days after onset, together with changes in infarct volume on magnetic resonance imaging. RESULTS: We found no serious adverse event, including change in leukocyte levels, which remained below 31,000/µL, at 150 and 300 µg G-CSF/body/day. Clinical outcome scores did not show any significant difference among the 3 groups. Chronological changes in infarct volume also showed no significant difference. CONCLUSIONS: G-CSF was well-tolerated at 150 and 300 µg/body/day in patients with acute ischemic stroke. However, administration of G-CSF at both 150 and 300 µg/body/day neither contributed to functional recovery nor reduced infarct volume at 3 months after onset, compared with the control group. The apparent lack of effectiveness may have been due to the small sample size. A trial of combination therapy with recombinant tissue plasminogen activator and G-CSF is planned.

Retrospective analysis of parkinsonian patients exhibiting normal (123)I-MIBG cardiac uptake.

BACKGROUND: Although most patients with Parkinson's disease (PD) show decreased cardiac (123)I-metaiodobenzylguanidine (MIBG) uptake, some exhibit normal uptake. We evaluated the clinical characteristics of such patients. METHODS: We enrolled 154 non-demented patients showing parkinsonism with normal cardiac MIBG uptake and had been clinically followed up during 29.9 ± 27.6 months. We defined the patients who did not fit the exclusion criteria for PD and demonstrated ≥ 30% reduction in the Unified Parkinson's Disease Rating Scale (UPDRS) motor score after anti-Parkinson agent administration as probable PD. We compared clinical characteristics and the cardiac MIBG heart-to-mediastinum (H/M) ratio between the probable PD group (N=37) and other groups (N=117). RESULTS: The probable PD group showed significantly higher UPDRS motor scores and greater incidence of tremor/rigidity than those of other groups. In addition, they showed a significantly lower cardiac MIBG H/M ratio in the delayed phase (delayed, p<0.0001). Washout-rate (WR) was significantly higher in probable PD cases (p<0.0001). Among 16 probable PD patients undergoing serial cardiac MIBG scintigraphy, the delayed phase cardiac MIBG H/M ratio showed a significant decrease and WR significantly increased during follow-up periods. CONCLUSIONS: An increase in WR and lower delayed phase cardiac MIBG uptake were found to be characteristics of such patients.

Voriconazole-responsive disseminated nodular lesions on spinal MRI.

A 74-year-old woman was hospitalized due to dysuria, weakness and dysesthesia of the lower extremities. She was in an immunosuppressed state following the administration of methylprednisolone therapy for idiopathic interstitial pneumonia. Cerebrospinal fluid and blood cultures were negative, and no infectious biomarkers were found. A gadolinium (Gd)-enhanced T1-weighted image of magnetic resonance imaging (MRI) revealed disseminated nodular lesions along the spinal cord. We suspected a diagnosis of seronegative deep mycosis and initiated anti-fungal therapy with voriconazole, which subsequently alleviated all of the patient's symptoms and MRI findings. Therefore, the presence of Gd-enhanced disseminated nodules on spinal MRI may be a good marker of deep meningeal mycosis.

Histone deacetylase inhibitor attenuates neurotoxicity of clioquinol in PC12 cells.

Clioquinol is considered to be a causative agent of subacute myelo-optico neuropathy (SMON), although the pathogenesis of SMON is yet to be elucidated. We have previously shown that clioquinol inhibits nerve growth factor (NGF)-induced Trk autophosphorylation in PC12 cells transformed with human Trk cDNA. To explore the further mechanism of neuronal damage by clioquinol, we evaluated the acetylation status of histones in PC12 cells. Clioquinol reduced the level of histone acetylation, and the histone deacetylase (HDAC) inhibitor Trichostatin A upregulated acetylated histones and prevented the neuronal cell damage caused by clioquinol. In addition, treatment with HDAC inhibitor decreased neurite retraction and restored the inhibition of NGF-induced Trk autophosphorylation by clioquinol. Thus, clioquinol induced neuronal cell death via deacetylation of histones, and HDAC inhibitor alleviates the neurotoxicity of clioquinol. Clioquinol is now used as a potential medicine for malignancies and neurodegenerative diseases. Therefore, HDAC inhibitors can be used as a candidate medicine for the prevention of its side effects on neuronal cells.

Lipid rafts and their possible involvements in neuroimmunological disorders.

Multiple sclerosis (MS) and neuromyelitis optica (NMO) are presumed to be an autoimmune disease in the central nervous system (CNS). Although lipids are most abundant components in the nervous system, it has been believed that cellular and/or humoral immunity to various myelin proteins causes these neuroinflammatory diseases. Recent research advances enable us to study lipids in the membranes and some key molecules involved in various neurological disorders including Guillain-Barré syndrome, Alzheimer's disease, Parkinson's disease, and prion disease, are localized in lipid rafts. In MS and NMO, the key molecules for the pathogenesis or the target molecules for the treatments of MS and NMO are also localized in lipid rafts. Here in this article, we highlight on the possible involvement of lipid rafts in the pathogenesis and treatment of MS and NMO and introduce our recent observation of aquaporin 4 regarding NMO.

Targeting of aquaporin 4 into lipid rafts and its biological significance.

Neuromyelitis optica (NMO) is an inflammatory demyelinating disease of the central nervous system and is considered to be caused by the binding of NMO-IgG to aquaporin 4 (AQP4) on astrocytes, which initiates complement-dependent cytotoxicity. AQP4 has two isoforms, i.e., M1 and M23. AQP4 is considered to form heterotetramers containing both isoforms in vivo. Most of the previous studies were performed using either one of the isoforms expressing cell lines. In this study, we generated a fluorescent epitope-tagged AQP4 M1 and M23 co-expressing astrocyte cell line and examined the subcellular targeting of AQP4. In this cell line, AQP4 was targeted mostly to membrane lipid rafts fraction evidenced by sucrose density gradient ultracentrifugation followed by Western blotting with anti-AQP4 antibody. Cholesterol depletion with methyl-ß-cyclodextrin or simvastatin resulted in the dislocation (relocation) of AQP4 from lipid rafts to non-rafts fraction of the membrane and AQP4 was not internalized intracellularly. This change in the localization of AQP4 on membrane significantly reduced complement-dependent cytotoxic effects of NMO-IgG obtained from patients with NMO without affecting AQP4 orthogonal arrays. Thus, these data strongly suggest that the targeting of AQP4 in the lipid rafts is closely related to the pathogenic effects of NMO-IgG.

[Neurological involvement in Wegener's granulomatosis].

Abstract Wegener's granulomatosis is a rare autoimmune disease associated with granulomatous inflammation and anti-neutrophil cytoplasmic antibody (ANCA)-associated small vessel vasculitis. Following the discovery of ANCA, ANCA-associated vasculitis is established as a disease entity of Wegener's granulomatosis, microscopic polyangiitis, and Churg-Strauss syndrome. Clinical and experimental studies have provided evidences that myeloperoxidase (MPO) and proteinase 3 (PR3), which are major antigenic targets for ANCA in neutrophils, are not only disease markers but also involved in the pathogenesis. In addition, recent studies have revealed another potential antigen for ANCA, lysosomal-associated membrane protein-2 (LAMP-2). Though nervous system manifestations of Wegener's granulomatosis are less frequent than classical manifestations in the lungs and kidneys, 20-50% of patients demonstrate neurological involvements. Peripheral nervous system involvement (in generalized Wegener's granulomatosis) is more frequent than central nervous system (CNS) involvement. Multiple mononeuropathy and multiple cranial neuropathy are the most prevalent symptoms. CNS manifestations include cerebrovascular events, pachymeningitis, seizures, and reversible posterior leukoencephalopathy syndrome. Here we discuss the pathogenic mechanism of ANCA and review the literature regarding neurological involvement in Wegener's granulomatosis.

Abnormal cross-talk between mutant presenilin 1 (I143T, G384A) and glycosphingolipid biosynthesis.

Mutations in the presenilin 1 (PS1) gene are associated with early onset familial Alzheimer's disease (FAD). In this study, we found that the expression of mutant-PS1 in stable transfectants of SH-SY5Y neuroblastoma cells results in a reduction of the biosynthesis and steady-state levels of glucosylceramide. As an in vivo corroboration of these data, there was a significant reduction of brain glucosylceramide and gangliosides in an animal model of FAD. In mutant-PS1-transfectants (I143T, G384A), immunocytochemistry disclosed a remarkable reduction of glucosylceramide synthase (GlcT-1)-like immunoreactivity in the cells when compared with those of mock- and wild-PS1 transfectants. Immunoprecipitation of GlcT-1 protein from mutant-PS1 transfectants demonstrated a marked reduction in GlcT-1 protein, but there was no reduction in the levels of GlcT-1 mRNA. Both coprecipitation and γ-secretase inhibition experiments suggest that mutant-PS1 seems to form a complex with GlcT-1 protein and to be involved in GlcT-1 degradation, which was never found in other cell types. Thus, mutations in the PS1 gene result in profound glycosphingolipids abnormalities by abnormal molecular interaction with GlcT-1.

[Hypertrophic pachymeningitis: three adult cases and a review of the literature].

Hypertrophic pachymeningitis (HP) is thought to have an autoimmune etiology but its precise cause and treatment remains to be elucidated. Here, we report the clinical details and therapeutic responses of 3 patients with HP and reviewed 66 previously reported cases in the literature. Among these patients, headache was the most frequent complaint. Cranial nerve involvement was also frequently observed, with the optic nerve being the most frequently impaired followed by the oculomotor, trochlear, and abducens nerves in frequency. Elevated C-reactive protein levels and erythrocyte sedimentation rates were found in approximately 97% of the patients. Steroids were the most commonly prescribed therapy, but no definite protocols for the standard dose and duration in HP have been proposed thus far. The average initial dose of prednisolone (PSL) was 42.7 mg/day, and the average maintenance dose was 12.4 mg/day in the chronic stage. Recurrence occurred in many patients when the dose of PSL was reduced to under 20 mg/day. Therefore, steroids should be tapered extremely slowly.

Transient splenial lesion of the corpus callosum in H1N1 influenza virus-associated encephalitis/encephalopathy.

A 26-year-old man was admitted to our hospital because of high fever, drowsiness, memory disturbance, and disorientation due to H1N1 influenza virus-associated encephalitis/encephalopathy. All of his symptoms rapidly improved following methylprednisolone pulse therapy. The diffusion-weighted image of brain magnetic resonance imaging (MRI) revealed a large transient hyperintense signal lesion on the central splenium of the corpus callosum. This MRI finding in conjunction with a complete clinical recovery has been previously observed in cases of clinically mild seasonal influenza-associated encephalitis/encephalopathy, and can be also a useful clue for the diagnosis of new type of influenza, H1N1 influenza virus infection complicated by encephalitis/encephalopathy.

Neurotrophin levels in cerebrospinal fluid of adult patients with meningitis and encephalitis.

BACKGROUND: The data on cerebrospinal fluid (CSF) levels of neurotrophins (NTs) in patients with meningoencephalitis are scarce, especially in adult patients. METHODS: We measured CSF levels of NTs such as nerve growth factor (NGF), brain-derived neurotrophic factor, and neurotrophin-3 (NT-3) in adult patients with various meningitis (n = 10) and encephalitis (n = 10) in both acute phase and recovery phase and adult control subjects (n = 21) by the enzyme-linked immunosorbent assay for NTs. RESULTS: Data show that NGF and NT-3 CSF levels were markedly elevated in the patient group in the acute phase compared with non-neurological controls (p < 0.001 and p < 0.05, respectively) and later returned to the levels of controls. Most intriguingly, we only recognized a significant correlation between NGF and NT-3 CSF levels in the patients in the acute phase. CONCLUSION: Such strong correlation of NGF and NT-3 CSF levels strongly suggests that in adult patients, some common regulatory mechanism(s) might be present among various kinds of NTs to cope with central nervous system infection.

Anti-GM1 antibodies affect the integrity of lipid rafts.

Previous studies have shown that patients with the axonal form of Guillain-Barré syndrome (GBS) develop autoantibodies against GM1 ganglioside (GM1). Nerve growth factor (NGF) is essential for neuronal survival in vivo and its functional receptor is Trk-tyrosine kinase. Here, we examined the biological effects of sera from patients with the axonal form of GBS on the morphology and the phosphorylation state of Trk-tyrosine kinase in PC12 cells. Furthermore, we examined the effect of the sera on the integrity of membrane lipid rafts biochemically. The data show that anti-GM1 antibodies found in patients' sera but not control sera inhibit NGF-induced Trk autophosphorylation. Most intriguingly, the autoantibodies alter the distribution of Trk in lipid rafts without shifting the distribution of a rafts marker protein. These data strongly suggest that anti-GM1 antibodies directly influence the integrity of the signaling platform, lipid rafts, implicating the importance of lipid rafts in the development of this disorder.

Novel therapeutic approach for Alzheimer's disease by removing amyloid beta protein from the brain with an extracorporeal removal system.

The accumulation of amyloid beta (Abeta) protein in the brain reflects the cognitive impairment noted in Alzheimer's disease. Recent studies have shown that brain Abeta disappeared and cognitive improvement occurred as a result of passive or active Abeta immunization. Peripheral administration of nonimmunization substances, such as GM1 ganglioside, also reduced brain Abeta. Therefore, we hypothesized that the rapid removal of Abeta from the blood by an extracorporeal system may act as a peripheral Abeta sink from the brain. In the present study, we investigated the Abeta removal activity of medical materials as a first step toward the design of an Abeta removal system. First, the removal activities of six materials were studied for Abeta(1-40) and Abeta(1-42) by batch analysis in albumin solution or in human plasma for 1-16 h. Two of the six materials reduced the Abeta concentrations by 90-99% within 1 h. Next, the two effective materials, hexadecyl-alkylated cellulose particles (HDC) and charcoal, were analyzed in a continuous single-pass system with minicolumns. Both materials showed around 81-90% removal activity for more than 2 h, which corresponded to over 4 l of plasma treatment in humans. In a human extracorporeal system, HDC also removed both Abeta(1-40) and Abeta(1-42) from whole blood circulation. In conclusion, biomedical materials were found that could remove Abeta(1-40) and Abeta(1-42) effectively in an extracorporeal system. It is now conceivable that further studies can be undertaken to reduce Abeta concentrations in the brain to improve cognitive function.

Clioquinol inhibits NGF-induced Trk autophosphorylation and neurite outgrowth in PC12 cells.

Clioquinol is considered to be a causative agent of subacute myelo-optico neuropathy (SMON), although the pathogenesis of SMON is yet to be elucidated. To investigate the mechanism of neurotoxicity of clioquinol, we used PC12 cell line and focused on nerve growth factor (NGF) signaling through Trk receptor, which is essential for survival and differentiation of neuronal cells. Clioquinol inhibited NGF-induced Trk autophosphorylation in a dose-dependent manner. This inhibitory activity was further confirmed by the data of the inhibition of NGF-induced mitogen-activated protein kinase (MAPK) phosphorylation, which is located in the down stream of NGF-Trk intracellular signaling pathway. Clioquinol also caused neurite retraction induced by NGF and cell death. NGF-stimulated (differentiated) cells were more vulnerable than naïve cells. These results strongly suggest that clioquinol may cause the perturbation of the intracellular survival pathway by inhibiting Trk-initiated signaling pathway.

Acute autonomic, sensory and motor neuropathy: successful treatment with IVIg.

Acute autonomic, sensory and motor neuropathy (AASMN) is a rare peripheral nerve disorder characterized by prominent dysautonomia with somatic sensory and motor impairment. Dysautonomia in AASMN is intractable even with corticosteroid therapy or plasmapheresis. Here we report a case of AASMN with severe orthostatic hypotension. Although the effectiveness of corticosteroid was insufficient, high dose intravenous immunoglobulin therapy (IVIg) was effective for not only sensorimotor symptoms but also autonomic symptoms. This is the first case of AASMN showing favorable responses to IVIg treatment, suggesting that IVIg should be considered when corticosteroid therapy or plasmapheresis is ineffective or insufficient.

Expression of L* protein of Theiler's murine encephalomyelitis virus in the chronic phase of infection.

The DA strain and other members of the TO subgroup of Theiler's murine encephalomyelitis virus synthesize the L* protein from an alternative initiation codon. L* is considered to play a key role in viral persistence and demyelination in susceptible strains of mice, although this hypothesis is still controversial. By using a mutant virus that expresses FLAG epitope-tagged L*, it was demonstrated previously that L* is expressed exclusively in neurons in vivo in the acute phase of infection in the central nervous system (CNS). However, in the mutant virus, the C-H-C-C zinc-binding motif in the leader protein (L) was disrupted by the insertion of the FLAG epitope, resulting in clearance of the virus from the CNS. Therefore, a further two mutant viruses were newly generated, expressing FLAG epitope-tagged L* in which the C-H-C-C zinc-binding motif within L is spared. Both mutant viruses caused persistence and demyelination successfully in spinal cords and enabled us to identify L* immunohistochemically in the demyelinating lesions.

Theiler's murine encephalomyelitis virus leader protein amino acid residue 57 regulates subgroup-specific virus growth on BHK-21 cells.

Strains of Theiler's murine encephalomyelitis virus (TMEV) are divided into two subgroups, TO and GDVII. TMEV strains show subgroup-specific virus growth and cell tropism and induce subgroup-specific diseases. Using site-directed mutagenesis, we demonstrated that the amino acid at position 57 of the leader protein (L(57)), which is located at the most N-terminal part of the polyprotein, regulates subgroup-specific virus growth on BHK-21 cells. Further study suggested that L(57) may regulate viral RNA encapsidation, although it does not affect the synthesis of viral proteins or the assembly of viral intermediates.

Leader (L) and L* proteins of Theiler's murine encephalomyelitis virus (TMEV) and their regulation of the virus' biological activities.

Theiler's murine encephalomyelitis virus (TMEV) is divided into two subgroups on the basis of their different biological activities. GDVII subgroup strains produce fatal poliomyelitis in mice without virus persistence or demyelination. In contrast, TO subgroup strains induce demyelinating disease with virus persistence in the spinal cords of weanling mice. Two proteins, whose open reading frames are located in the N-terminus of the polyprotein, recently have been reported to be important for TMEV biological activities. One is leader (L) protein and is processed from the most N-terminus of the polyprotein; its function is still unknown. Although the homology of capsid proteins between DA (a representative strain of TO subgroup) and GDVII strains is over 94% at the amino acid level, that of L shows only 85%. Therefore, L is thought to be a key protein for the subgroup-specific biological activities of TMEV. Various studies have demonstrated that L plays important roles in the escape of virus from host immune defenses in the early stage of infection. The second protein is a 17-18 kDa protein, L*, which is synthesized out-of-frame with the polyprotein. Only TO subgroup strains produce L* since GDVII subgroup strains have an ACG rather than AUG at the initiation site and therefore do not synthesize L*. 'Loss and gain of function' experiments demonstrate that L* is essential for virus growth in macrophages, a target cell for TMEV persistence. L* also has been demonstrated to be necessary for TMEV persistence and demyelination. Further analysis of L and L* will help elucidate the pathomechanism(s) of TMEV-induced demyelinating disease.