Recently, inflammation has been implicated in the progression of cerebral ischemic injury. Especially, T lymphocytes have been shown to infiltrate into the ischemic brain 24 hours after the onset, however, the function and specific subpopulation of these infiltrated T lymphocytes have not been fully understood.
By using cytokine-deficient mice with transient focal ischemia model, we have shown that IL-23 and IL-17 but not IL-6 or IFN-γ play pivotal roles in the ischemic brain injury. We found that IL-23, which was mainly produced from infiltrated macrophages, induced IL-17-producing T lymphocytes in the ischemic brain. IL-23 and IL-17 expression increased 1 day or 3 day after ischemic injury, respectively, and promoted inflammatory responses by increasing the expression of neurotoxic factors. To our surprise, IL-17 was mainly produced by γδT lymphocytes, but not helper T cells.
Based on these findings, we have tried to develop new therapeutic strategy for the progression of brain infarction. We found that administration of FTY720 (Fingolimod) and antibody against γδT lymphocytes attenuated ischemic brain damage. Furthermore, antibody against p40 which neutralizes both IL-23 and IL-12 simultaneously was also effective. Therefore, anti-cytokine therapy will be applicable for neuroprotection in the delayed phase of brain ischemia.

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Neuroblasts in the subventricular zone proliferate markedly after stroke, and migrate to the site of injury along with blood vessels. However, a large fraction of stroke-generated neuroblasts die shortly after being born, because of local inflammation.
E-selectin is specifically expressed on endothelial cells, but only when the endothelium activates. Since endothelial activation occurs after stroke, E-selectin can serve as an immunologic tolerization antigen that can focus immunomodulation to regions of the vascular tree. Intranasal instillation of recombinant E-selectin will induce mucosal tolerance to that antigen with the generation of E-selectin-specific regulatory T cells (Tregs). Tregs may protect newly-generated neuroblasts from ischemic damage through 'bystander suppression' in which immunomodulatory cytokines such as TGF-β and IL-10 are released locally. In this series of experiments, we have shown that after E-selectin tolerization in permanent middle cerebral artery occlusion (pMCAO) rats Tregs transmigrate to the peri-infarct region of ischemic brain, TNF expression in the local neurovascular niche is reduced, and the survival of newly generated neuroblasts or neurons in the peri-infarct region is increased. Under these conditions, an improvement in sensorimotor function after pMCAO also occurs.
E-selectin-specific Tregs can modulate the efficacy of adult neurogenesis after ischemia and promote repair after brain injury.

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Here we propose multidimensional non-invasive imaging to understand the functional anatomy of neural circuits of the human brain. The multidimensional network imaging technique currently employs anatomical, functional and evoked connectivity imaging in various combinations. The anatomical and functional connectivity imaging can be achieved by the analysis of diffusion-weighted and functional magnetic resonance imaging (fMRI), respectively. New analysis techniques such as probabilistic diffusion tractography and tract-based statistics have refined the anatomical connectivity imaging, especially in combination with fMRI for setting up regions-of-interest. For the evoked connectivity imaging, brain stimulation technique such as transcranical magnetic stimulation (TMS) is performed during acquisition of fMRI and electrophysiology monitoring. Despite technical challenges, it is important to put information from these different modalities for network imaging together for fair understanding of human brain functions.

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A new definition of transient ischemic attack (TIA) was proposed by the working group of the American Heart Association and the American Stroke Association in 2009. In this definition, TIA is defined as a transient episode of neurological dysfunction caused by focal brain, spinal cord, or retinal ischemia, without acute infarction. This definition is currently much argued, and has not yet been globally accepted. There would be no meaning to differentiate TIA from ischemic stroke only by the duration of symptoms. Because, TIA in acute setting and acute ischemic stroke share the same spectrum. Therefore, we proposed a new clinical concept termed acute cerebrovascular syndrome (ACVS), which includes acute TIA and acute ischemic stroke. Patients early after TIA are at high risk of stroke and thus should be immediately evaluated and treated as a medical emergency, that is, ACVS. An international multicenter cooperative registry study is ongoing in 5,000 patients with TIA or minor stroke within 7 days after the onset, who will be followed up for 5 years, involving Japanese patients.

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The diagnostic criteria and management strategy of transient ischemic attack (TIA) have drastically changed for these years. In Europe and the United States, community and hospital-based studies demonstrated a higher risk of stroke immediately after a TIA than previously considered. Urgent evaluation and immediate initiation of treatment reduces stroke after a TIA dramatically. We establish the Japan TIA research group, which is subsidized by the Ministry of Health, Labour, and Welfare, Japan. The group conducted a nation-wide survey using a questionnaire and a retrospective registration study to clarify the current status of clinical practice of TIA in our country. We are also preparing a prospective, nation-wide, multicenter registration study of TIA patients. These topics were reviewed in this symposium.

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In the past, transient ischemic attack (TIA) was defined as any sudden, focal cerebral ischemic event with neurological deficit lasting <24 hours. However, in several series of patients with TIA who underwent diffusion-weighted magnetic resonance imaging, many ischemic episodes with symptoms lasting <24 hours are associated with new infarctions. Therefore, TIA working group proposed a new tissue-based, rather than a time-based, definition of TIA: "a brief episode of neurological dysfunction caused by a focal disturbance of brain or retinal ischemia, with clinical symptoms typically lasting less than 1 hour, and without evidence of infarction". The latest definition of TIA is "a transient episode of neurological dysfunction caused by focal brain, spinal cord, or retinal ischemia, without acute infarction".
Recent studies have shown that stroke risk after TIA is high in the first few days. Two prognostic scores for short-term risk of stroke after TIA have been proposed: the California score and the ABCD score. The ABCD² score has the same components as ABCD, but with diabetes mellitus added. This score was a more accurate predictor than either of the previous scores.
Antiplatelet therapy should be prescribed immediately for the secondary prevention of stroke in patients with a noncardioembolic TIA.

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Small deep brain infarcts are often caused by two different vascular pathologies: 1. atheromatous occlusion at the orifice of large caliber penetrating arteries termed branch atheromatous disease (BAD) and 2. lipohyallinotic degenerative changes termed lipohyalinitic degeneration (LD). Atheromatous changes at the origin or proximal portion of a penetrating artery of larger caliber can be observed in infarcts of the lenticulostriate (LSA) as well as the anterior pontine arteries (APA). We studied 392 patients with penetrating artery disease in the territories of LAS and APA to evaluate predictive factors for progressive motor deficits (PMD). Prevalence of male gender, diabetes mellitus and intracranial atherosclerosis were significantly higher in the APA group than in the LSA group. Female sex and initial severity of motor deficit were common predictors for PMD in both groups. In the LSA group, single infarcts without concomitant silent lacunar infarcts and lacunar TIAs were found to be independent predictors for PMD. In the APA group, diabetes mellitus was found to be an independent predictor. Combined treatment consisting of argatroban, cilostazol, and edaravone for acute BAD type infarct significantly improved the functional outcome.

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分枝粥腫病BADはわが国では欧米にくらべ頻度が高く，多くが治療抵抗性で進行性増悪の経過を辿ることが特徴である．BADにおける危険因子・背景因子と進行性増悪に関連する因子は多岐にわたり，病態の解明を困難としている．アテローム血栓性脳梗塞・ラクナ梗塞に準じた画一的な抗血小板療法では進行性増悪を予防できず，機能予後も改善しない．現状では白質傷害の進行抑制を考慮した多剤カクテル療法により機能予後の改善が期待できる．BADに関して今後さらなるエビデンスの蓄積が重要である．

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To investigate the longitudinal course of Japanese patients with Amyotrophic Lateral Sclerosis (ALS), we constructed a multicenter registration and follow-up system called Japanese Consortium for Amyotrophic Lateral Sclerosis research (JaCALS). Genomic DNA samples of ALS patients were stored and linked to the clinical information. We designed a telephone survey system using a clinical research coordinator (CRC) to check the score of the ALS Functional Rating Scale-R (ALSFRS-R) and the prognosis every 3 months. In January 2006, we began registering ALS patients, and, at present, 19 neurology facilities are participating in the JaCALS. Currently, 421 Japanese ALS patients are registered. The longitudinal courses and prognoses of 93% of the 284 patients over a year from registration have been recorded in this system. In collaboration with the RIKEN Center for Genomic Medicine, genome-wide association studies (GWAS) for ALS susceptibility genes were conducted using 981 ALS samples from the JaCALS and BioBank Japan. Novel associated genes were identified, and replication studies are underway.
JaCALS has established an efficient registration and follow-up system with genomic DNA resources of ALS patients, and will contribute to identify ALS-associated genes and to promote clinical researches.

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遺伝性痙性対麻痺（Hereditary Spastic Paraplegia：HSP）は下肢の痙縮と筋力低下を呈する神経変性疾患群であり，現在，SPG1～48の遺伝子座と20を越える原因遺伝子が同定されている．HSPは同じ病型でも家系内・家系間で多彩な臨床像を呈することや，逆にことなる病型でもよく似た臨床像を呈することが知られており，臨床像のみでHSPの病型診断をおこなうのはきわめて困難である．全国多施設共同研究体制であるJapan Spastic Paraplegia Research Consortium（JASPAC）では，HSPの網羅的な遺伝子診断サービスを提供している．今後，JASPACにより，本邦HSPの分子疫学と分子病態が明らかにされ，治療法開発へと向かうことが期待される．

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Proteomic and immunochemical analyses have shown that hyperphosphorylated TDP-43 is a major component of ubiquitin-positive inclusions from brain of frontotemporal lobar degeneration (FTLD) patients. In 2008, TDP-43 gene mutations were discovered in familial and sporadic amyotrophic lateral sclerosis (ALS), indicating that TDP-43 protein abnormality is associated with neurodegeneration. We raised antibodies against 36 synthetic phosphopeptides and demonstrated that abnormal phosphorylation takes place in the C-terminal region of TDP-43. One antibody, pS409/410, stained the inclusions in both FTLD and ALS brains, with no nuclear staining. Immunoblotting revealed the presence of hyperphosphorylated 45kDa band, smearing substances and 18-26kDa fragments in deposits, and the band patterns were different between FTLD and ALS. Overexpression of TDP-43 C-terminal fragments as GFP-fusions resulted in formation of inclusions positive for antibodies to phosphorylated TDP-43 and ubiquitin. We further investigated the protease-resistant TDP-43 and found that it is also different between ALS and FTLD, supporting the idea that the different band patterns reflect different conformations of abnormal TDP-43. Interestingly, the C-terminal band pattern is indistinguishable among brain regions and spinal cord in each individual patient. These results suggest that abnormal TDP-43 produced in a cell may be transferred to different regions and propagated during disease progression.

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The molecular pathogenesis of amyotrophic lateral sclerosis (ALS) is unclear. TAR DNA-binding proteins of 43 KDa (TDP-43) immunopositive cytoplasmic inclusions have been found in glia and neurons of ALS patients. The discovery of TDP-43 mutations in ALS patients indicates a direct role of TDP-43 in ALS. More than 30 mutations in the TDP-43 gene have been identified in patients with familial and sporadic ALS. ALS with a TDP-43 mutation is classified as ALS-10. The clinical features of ALS-10 are quite similar to those of sporadic ALS. Furthermore, the neuropathological findings for ALS-10, including TDP-43 immunopositive inclusions and Bunina bodies, are identical to those in sporadic ALS. Most of the mutations are located in the C-terminus of TDP-43, which may function as a binding domain of heterogeneous nuclear ribonucleoprotein. Frontotemporal lobar degeneration: FTLD and FTLD/MND (motor neuron disease) also have TDP-43 immunopositive inclusions. These disorders have been named as TDP-43 proteinopathy. However, patients with TDP-43 mutations rarely develop FTLD. Causative genes for familial FTLD and FTLD/MND are not linked to the TDP-43 gene. Thus, other factors may contribute to the TDP-43 pathology in these diseases. Further analysis is required to elucidate the molecular mechanism of ALS-10 and TDP-43 proteinopathy.

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Formation of intracellular aggregates is the hallmark of polyglutamine (polyQ) diseases. We analyzed the components of purified nuclear polyQ aggregates by mass spectrometry. As a result, we found that the RNA-binding protein translocated in liposarcoma (TLS) was one of the major components of nuclear polyQ aggregate-interacting proteins in a Huntington disease cell model and was also associated with neuronal intranuclear inclusions of polyQ diseases. In vitro study revealed that TLS could directly bind to truncated N-terminal huntingtin (tNhtt) aggregates but could not bind to monomer, indicating that the tNhtt protein acquired the ability to sequester TLS after forming aggregates. Immunohistochemistry showed that TLS was associated with neuronal intranuclear inclusions of Huntington disease and other poly Q disease brains. After this report, FUS/TLS was reported as a responsible gene for ALS6. Because TLS has a variety of functional roles, the sequestration of TLS to polyQ aggregates may play a role in diverse pathological changes in the brains of patients with polyQ diseases and ALS6.

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FUS/TLS is identified as the causative gene of ALS6. FUS/TLS shares a role in nuclear protein as RNA editing with TDP43, and aggregates in basophilic inclusions (BIs) in ALS6 as well as juvenile ALS with BIs. FUS/TLS is also associated with atypical frontotemporal lobar degeneration (aFTLD), neuronal intermediate inclusion body disease (NIBD) and basophilic inclusion body disease (BIBD). Thus, FUS/TLS as well as TDP43 may provide clues to motor neuron disease (MND) and frontotemoporal dementia (FTD). We have established consortium to study MND/FTD in collaboration with neurological, psychiatric and geriatric institutes. Two clinically sporadic ALS-FUS/TLS cases were selected from the consortium: a case of ALS6 without family history and a case of juvenile ALS with BIs. Both cases presented with BIs, which were immunoreactive for anti-FUS/TLS antibodies and ultrastructurally consisted of granulofilamentous profiles common to ubiquitin-immunoreactive inclusions. Two familial ALS6 cases were also studied in the consortium. Biochemical analysis showed no truncation, phosphorylation or ubiquitination of FUS in insoluble fraction, that shows clear difference from TDP43. The mechanism of FUSopathy is currently a challenging theme from the point of protein aggregation.

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Molecular genetic studies, positional cloning in particular, contributed to progresses in neurology. However, because of a bottleneck of low sequence analysis throughput, large proportions of small families, especially of late-onset hereditary diseases, still remain to be elucidated. The massively parallel sequencers are expected to identify causative genes in such a small but meaningful families and to reveal pathophysiology of the diseases.
Multiple system atrophy (MSA) is a neurodegenerative disorder. Pathophysiology of MSA remains largely uncertain despite many studies. Generally, MSA is a sporadic disorder, but there are rare familial aggregations which would provide a strong clue to understand pathophysiology of MSA.
With the backgrounds, we analyzed an MSA family with 2 pathologically proven siblings born with consanguineous parents. Linkage study revealed a candidate 70Mb regions in four chromosomes. We carried out whole-genome resequencing of the proband using Illumina GAIIx. Mean depth was 58X, and a total of 3.5 million single nucleotide variations were found.
Although the new technologies are highly powerful, to find a mutation from a number of variations, a challenge with bioinformatics should be overcome. Coping with the problem, the high-throughput sequence technologies will further contribute to a breakthrough in neurology.

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The symptoms of idiopathic normal pressure hydrocephalus (iNPH) are generally seen in aged, and iNPH has been overlooked or misdiagnosed. In Japan, since the Clinical Guidelines were published, remarkable progress are noted in the recognition of it and clinical researches for it. In this paper, recent progress diagnostic measures for iNPH is discussed, focusing on the key role of clinical features, neuroimagings, and tap test. As for clinical symptoms, in particular the distinctive features of cognitive and behavioral symptoms have been delineated. The clinical significance of MRI features of iNPH, i.e., ventriculomegary with tight high convexty/midline subarachnoid spaces and enlarged Sylvian fissures, have been validated in a prospective cohort study, Study of Idiopathic Normal Pressure Hydrocephalus on Neurological Improvement (SINPHONI). Disproportionately enlarged subarachnoid-space hydrocephalus (DESH) has been proposed to designate iNPH with these MRI features consisting of a major proportion of iNPH. Although tap test is useful in diagnosis and in making decision of shunt surgery, the results of SINPHONI suggest that its procedure needs to be refined to increase the diagnostic accuracy.

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We investigated if there are individuals at a preclinical stage of idiopathic normal pressure hydrocephalus (iNPH) in a general population. All the residents aged 61 years and 70-72 years in the two communities of Japan (n=1142) were requested to take brain MRI examination. 790 residents (69.2%) participated in this study. Among them, 51 individuals (6.46%) had the enlarged ventricles (Evans index of >0.3), 12 (1.52%) of which showed the iNPH features on MRI. Of the 12 individuals, 8 were asymptomatic, while 4 had gait disturbance and/or dementia (possible iNPH). During a follow-up period of 4-8 years, two of the 8 asymptomatic subjects developed dementia and/or gait disturbance. The prevalence of possible iNPH was 0.51% (4/790) among Japanese elderly (>61 years of age). Asymptomatic ventriculomegaly with the iNPH features on MRI (AVIM) may represent a preclinical stage of iNPH.
To identify a possible genetic change of AVIM and possible iNPH, we performed a genome-wide screening for copy number variations (CNV), and found that a segmental copy number loss of the SFMBT1 gene may be a genetic risk for the disease.

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Cerebrospinal fluids (CSF) hydrodynamics in normal and hydrocephalic brain was observed noninvasively using a time-spatial labeling inversion pulse (SLIP) technique. A time-SLIP technique applied label to CSF in the region of interest so that CSF became internal CSF tracer. CSF hydrodynamics even in normal brain appeared to be much different from it was imagine from conventional CSF physiology text books. Various amplitudes of pulsatile CSF flow were observed in the different regions of the brain. CSF hydrodynamics altered when hydrocephalus was developed. A time-SLIP CSF flow imaging is helpful to understand CSF hydrodynamics in the normal physiological and hydrocephalic brain. It may be useful to distinguish the hydrocephalus brain from the senile atrophic brain.

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