Hisashi Narai

Increased ER stress during motor neuron degeneration in a transgenic mouse model of amyotrophic lateral sclerosis.

Abstract The endoplasmic reticulum (ER), which plays important roles in apoptosis, is susceptible to oxidative stress. ER stress is also thought to be involved in the pathogenesis of neurodegenerative diseases. In this study, we investigated whether ER stress is involved in the pathogenesis of amyotrophic lateral sclerosis (ALS) using the anterior part of the lumbar spinal cord of transgenic mice carrying a mutation (G93A) in the superoxide dismutase 1 (SOD1) gene. Western blot and immunohistochemical analyses demonstrated that the expressions of p-PERK and p-eIF2α were increased in the microsome fraction (P3) of the lumbar spinal cord at the pre-symptomatic age of 12 weeks (12W), while the expression of activated caspase-12 was increased in the cytoplasmic fraction (S3) of the lumbar spinal cord at both the pre-symptomatic age of 12W and the late symptomatic age of 20W. In contrast, GRP78 did not show any increases in the microsome fraction (P3) of the lumbar spinal cord at either the pre-symptomatic or symptomatic ages. Thus, the present results strongly suggest that the balance between anti- and pro-apoptotic proteins related to ER stress is impaired from the pre-symptomatic stage in this ALS mouse model, and that this imbalance may be related to the pathogenesis of motor neuron degeneration in ALS.

Elevation of MCP-1 and MCP-1/VEGF ratio in cerebrospinal fluid of amyotrophic lateral sclerosis patients

Abstract Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease with progressive cell death of upper and lower motor neurons. In this study, we measured monocyte chemotactic protein-1 (MCP-1) and vascular endothelial growth factor (VEGF) levels in cerebrospinal fluid (CSF) and serum by enzyme-linked immunosorbent assay (ELISA) in 42 ALS patients, and compared these levels with those of control subjects with other neurodegenerative disorders or with those of normal controls. MCP-1 levels in CSF were significantly higher in ALS patients than in the control group. VEGF levels in CSF tended to be lower in ALS patients than in the control group, but not significantly. A positive correlation was found between MCP-1 levels in CSF of ALS patients and the total Norris scale. The elevation of MCP-1/VEGF ratio in CSF was more specific to ALS patients compared to other neurological diseases such as Parkinsons disease (PD) and spinocerebellar ataxia (SCA) and to controls. Our data suggested that both MCP-1 levels and MCP-1/VEGF ratio in CSF may be useful markers for the clinical diagnosis of ALS.

Intrathecal injection of epidermal growth factor and fibroblast growth factor 2 promotes proliferation of neural precursor cells in the spinal cords of mice with mutant human SOD1 gene

We investigated three steps of neural precursor cell activation—proliferation, migration, and differentiation—in amyotrophic lateral sclerosis spinal cord treated with intrathecal infusion of epidermal growth factor (EGF) and fibroblast growth factor 2 (FGF2) into the lumbar spinal cord region of normal and symptomatic transgenic (Tg) mice with a mutant human Cu/Zn superoxide dismutase (SOD1) gene. We observed that 5‐bromodeoxyuridine (BrdU) + nestin double‐labeled neural precursor cells increased in the spinal cords of Tg mice compared with non‐Tg mice, with a much greater increase produced by EGF and FGF2 treatment. The number of BrdU + nestin double‐labeled cells was larger than that of BrdU + ionized calcium‐binding adapter molecule‐1 (Iba1), BrdU + glial fibrillary acidic protein (GFAP), or BrdU + highly polysialylated neural cell adhesion molecule (PSA‐NCAM) double‐labeled cells, but none expressed neuronal nuclear antigen (NeuN). On further analysis of the gray matter of Tg mice, the number of BrdU + nestin and BrdU + PSA‐NCAM double‐labeled cells increased more in the ventral horns than the dorsal horns, which was again greatly enhanced by EGF and FGF2 treatment. Because neural precursor cells reside close to the ependyma of central canal, the present study suggests that proliferation and migration of neural precursor cells to the ventral horns is greatly activated in symptomatic Tg mice and is further enhanced by EGF and FGF2 treatment and, furthermore, that the neural precursor cells preferentially differentiate into neuronal precursor cells instead of astrocytes in Tg mice with EGF and FGF2 treatment.

Prevention of Spinal Motor Neuron Death by Insulin-Like Growth Factor-1 Associating With the Signal Transduction Systems in SODG93A Transgenic Mice

The role of insulin‐like growth factor‐1 (IGF‐1) in amyotrophic lateral sclerosis (ALS) and its mechanism of action are important from both pathogenic and therapeutic points of view. The present study investigated the changes of IGF‐1Rβ and the key intracellular downstream protein insulin receptor substrate‐1 (IRS‐1) by using SOD1G93A transgenic mice with continuous intrathecal IGF‐1 treatment. The number of lumbar spinal motor neurons was preserved with IGF‐1 treatment in a dose‐dependent manner. The numbers of immunopositive motor neurons for IGF‐1Rβ and IRS‐1 were not significantly different between wild‐type and Tg mice with vehicle treatment, whereas treatment of Tg mice with IGF‐1 decreased the numbers of immunopositive motor neurons in a dose‐dependent manner. On the other hand, the ratio of immunopositive motor neurons per total living motor neurons in vehicle‐treated mice was greatly increased in Tg mice with vehicle treatment compared with wild‐type mice. With IGF‐1 treatment, the ratio was dramatically decreased in a dose‐dependent manner. These results suggest that IGF‐1 treatment prevents motor neuron loss by affecting the signal transduction system through IGF‐1R and the main downstream signal, IRS‐1.

Reduction of a vascular endothelial growth factor receptor, fetal liver kinase-1, by antisense oligonucleotides induces motor neuron death in rat spinal cord exposed to hypoxia.

Vascular endothelial growth factor (VEGF) is reported to play a neuroprotective role through a VEGF receptor, fetal liver kinase-1 (Flk-1) in vitro. We investigated whether reduction of Flk-1 could induce motor neuron loss in rat spinal cord by inhibiting the expression of Flk-1 in rat spinal cord using antisense oligodeoxynucleotides (ODNs) against the Flk-1 receptor. Rat spinal cord was repetitively exposed to 12% hypoxia, and the change of the phosphatidylinositol 3-kinase (PI3-K)/Akt pathway and the mitogen-activated protein kinase kinase (MEK)/extracellular-signal-regulated kinase (ERK) pathway was examined. Intrathecal infusion of Flk-1 antisense ODNs for 7 days suppressed almost completely Flk-1 expression in the lumbar segment of the spinal cord and was followed by a hypoxic challenge with 12% oxygen for 1 h that was repeated for 7 more days. In the lumbar segment, we observed that reduced Flk-1 expression and hypoxic challenge for 7 days resulted in approximately 50% loss of motor neurons, in which the activation of Akt and ERK, that is, increased levels of phosphorylated-Akt and of phosphorylated-ERK by hypoxia, was markedly inhibited. In contrast, the reduction of Flk-1 expression alone did not induce motor neuron loss. These results suggest that VEGF exerts its protective effect on motor neurons against hypoxia-induced toxicity by the Flk-1 receptor through the PI3-K/Akt and the MEK/ERK signaling pathways.

Nocturnal blood pressure dip in CADASIL.

The influence of a nocturnal blood pressure dip on cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) has not yet been clarified. We attempted to examine a correlation with the nocturnal blood pressure dip and CADASIL. We monitored circadian blood pressure patterns by the use of a portable blood pressure monitoring device in five patients with CADASIL and 10 age- and sex-matched control subjects. Based on nocturnal fall in mean arterial blood pressure (MABP), we classified patients into extreme dippers (nocturnal reduction of MABP > or =20%), dippers (> or =10% but <20%), nondippers (<10% but > or =0%), and inverted dippers (<0%). Three patients revealed non-dipper and two inverted dipper. Nighttime MABP fall was significantly lower in patients compared with control subjects (P<0.01). This study suggests that a lower nocturnal blood pressure fall may be partly associated with incidence and/or worsening of deep white matter lesions in CADASIL.

Early detachment of neuromuscular junction proteins in ALS mice with SODG93A mutation

The transgenic animals with mutant copper/zinc superoxide dismutase (SOD1) DNA develop paralytic motor neuron disease resembling human amyotrophic lateral sclerosis (ALS) patients and are commonly used as models for ALS. In the transgenic (Tg) mice with the G93A mutation of the human SOD1 gene SOD1G93A mice), the loss of ventral root axons and the synapses between the muscles and the motor neurons suggested that the motor neuron degeneration might proceed in a dying-back degeneration pattern. To reveal the relationship between axonal degeneration and the progression of the muscle atrophy in the SOD1G93A mice, we investigated the status of the neuromuscular junction along the disease progression. As a presynaptic or postsynaptic marker of neuromuscular junction (NMJ), anti-synaptic vesicle protein 2 (anti-SV2) antibody and α-bungarotoxin (α-BuTX) were chosen in this study and, as a marker of synaptic cleft, anti-agrin antibody was chosen in this study. In the immunohistochemistry of α-BuTX and anti-SV2 antibody, the percentages of double positive NMJs among α-BuTX single positive were decreased in Tg mice through time from ten weeks. The number of postsynaptic acethylcholine receptor (AChR) clusters did not decrease in Tg mice even at the end stage. Immunohistochemistry of α-BuTX and anti-agrin antibody revealed that the increase of immunopositive area of anti-agrin antibody around the muscle fiber in Tg mice from ten weeks of age. In this study, we revealed that the detachment of nerve terminals started at ten weeks in Tg mice. The levels of AChR did not change throughout 5–20 weeks of age in both groups of mice, and AChR remains clustering at NMJs, suggesting that the muscle abnormality is the result of detachment of nerve terminals.

Isolated abducens nerve palsy caused by vascular compression

Causes of isolated abducens nerve palsy include aneurysms of the vertebral artery (VA), tumor, diabetes mellitus, and meningitis.1 Elongation of arteries of the vertebral basilar system occasionally causes facial nerve palsy or trigeminal nerve disturbance by compression. We describe a patient with isolated right abducens nerve palsy due to vascular compression of the elongated left VA. A 47-year-old man had a 2-year history of horizontal diplopia without other symptoms. Mild hypertension (149/97 mm Hg) was the only notable feature of his medical history. He complained of horizontal diplopia during rightward gaze and diplopia of primary position after drinking too much. Rightward saccades were hypometric. Edrophonium test was …

Intravenous thrombolysis with neuroprotective therapy by edaravone for ischemic stroke patients older than 80 years of age

BACKGROUND Alteplase, a recombinant tissue plasminogen activator (tPA), was approved for patients with acute ischemic stroke within 3 hours of stroke onset in Japan in October 2005 at a dose of 0.6 mg/kg. The aim of this study was to assess the safety and efficacy of alteplase in elderly patients in Japan. METHODS One hundred twenty-nine consecutive patients who were admitted to our 5 hospital groups and who received intravenous tPA within 3 hours of stroke onset between January 2010 and December 2011 were divided into 2 groups by age (<80 years of age [younger group] and >80 years of age [older group]) and by treatment with or without edaravone. Clinical backgrounds and outcomes were investigated. RESULTS The National Institutes of Health Stroke Scale score on admission was not different in both groups, but the National Institutes of Health Stroke Scale scores 7 days after stroke onset were significantly higher in the older group (score 8; P < .05) than in the younger group (score 4), and the ratio of patients with a modified Rankin Scale score of 4 to 6 was significantly greater in the older group (41.7%; P < .05) than in the younger group (22.2%). However, there was no difference in asymptomatic and symptomatic intracerebral hemorrhage rates between the younger and older groups (asymptomatic 20.2% v 18.8%; symptomatic 2.6% v 2.1%). Patients with edaravone showed a higher recanalization rate (61.9%; P < .01) and a better modified Rankin Scale score at 3 months poststroke (P < .01) than the nonedaravone group. CONCLUSIONS These data suggest that intravenous alteplase (0.6 mg/kg) within 3 hours of stroke onset was safe and effective, even for very old patients (≥ 80 years of age), but resulted in poor outcomes relating not to tPA but to aging. In addition, edaravone may be a good partner for combination therapy with tPA to enhance recanalization and reduce hemorrhagic transformation.

Serial diffusion-weighted MRI and SPECT findings in a Creutzfeldt-Jakob disease patient with V180I mutation

We report serial changes of diffusion-weighted imaging (DWI) and single photon emission computed tomography (SPECT) in a patient with Creutzfeldt-Jakob disease with V180I mutation (CJD180). DWI abnormalities in our patient were more predominantly observed in the left cerebral cortex than left basal ganglia. Hemilateral abnormalities progressed over 5 months to involve the contralateral side with increasing DWI signals. At 6 months, SPECT showed hypoperfusion in the left parietal and frontal lobes and the hypoperfusion region spread to the bilateral basal ganglia, right parietal and frontal lobes. SPECT imaging revealed marked cerebral blood flow reduction, predominantly in the cerebral cortex corresponding to brain areas with high-intensity DWI signals. During the follow-up period of CJD180, DWI was more sensitive than conventional FLAIR and T2-weighted images (T2WI) to detect and monitor the progression of abnormal hyperintense lesions. We suggest that serial DWI and SPECT findings are useful for not only early diagnosis of CJD but also for monitoring disease progression.