Masayasu Matsumoto

Association between central systolic blood pressure, white matter lesions in cerebral MRI and carotid atherosclerosis.

White matter hyperintensities (WMHs) observed on cerebral magnetic resonance images (MRIs) are associated with age and hypertension, suggesting a vascular mechanism of pathogenesis. Central systolic blood pressure (cSBP) correlates more closely with measures of cardiovascular disease risk than brachial pressure. We sought to determine whether cSBP correlates with WMHs and if cSBP is predictive of cerebrovascular disease. Radial applanation tonometric measurements for cSBP and augmentation index (AI) were carried out in unselected individuals undergoing carotid ultrasound. WMHs were assessed retrospectively using fluid-attenuated inversion recovery (FLAIR)-MRIs as periventricular (PVH) and deep white matter hyperintensities (DWMH), and they were rated using the Fazekas scale. A total of 179 patients, 94 (53%) men and 85 (47%) women, with a mean age of 66±13 years were included in the study. On MRI, 17, 74, 67 and 21 patients had PVH grades 0, 1, 2 and 3, respectively. Forty-eight, 69, 49 and 13 had DWMH grades 0, 1, 2 and 3, respectively. In our study population, PVH correlated with age, brachial SBP, cSBP and AI (r=0.49, 0.28, 0.23; P<0.002 and r=0.13; P<0.05, respectively). DWMH also correlated with age, brachial SBP and cSBP (r=0.41, 0.30, 0.22; P<0.003, respectively), but not with AI. cSBP values were associated with PVH/DWMH grades 2 and 3, but brachial SBP correlated only with grade 3. Mean carotid intima–media thickness (common carotid arteries (CCA)-IMT) was 0.68±0.13u2009mm. CCA-IMT and plaque score (PS) correlated with PVH/DWMH. Multivariate regression analysis showed cSBP, age and PS to be independently associated with PVH and DWMH. Correlation of cSBP with PVH and DWMH was independent of PS. Central SBP correlated with PVH and DWMH in FLAIR-MRIs and can better predict WMHs than brachial SBP in earlier stages.

A Randomized, Double-Blind Study Comparing the Safety and Efficacy of Clopidogrel versus Ticlopidine in Japanese Patients with Noncardioembolic Cerebral Infarction

Background: Patients treated with ticlopidine require careful hematologic monitoring. Clopidogrel may have greater tolerability. However, no direct comparison of these two drugs has been reported and evidence of improved safety with clopidogrel is not yet established in the Japanese population. A comparison of both agents was therefore conducted in Japanese stroke patients. Methods: Patients with noncardioembolic cerebral infarction were randomized to clopidogrel 75 mg or ticlopidine 200 mg once daily for 52 weeks. The primary endpoint was safety; the major secondary endpoint was the incidence of vascular events.Results: Clopidogrel was associated with significantly fewer safety events than ticlopidine (7.0 versus 15.1%; p < 0.001) and no significant difference in efficacy between the two treatments was seen [hazard ratio 0.977 (95% confidence interval: 0.488–1.957)].Conclusions: In Japanese stroke patients, clopidogrel 75 mg is better tolerated than ticlopidine 200 mg once daily.

Association between cerebral microbleeds on T2*-weighted MR images and recurrent hemorrhagic stroke in patients treated with warfarin following ischemic stroke.

BACKGROUND AND PURPOSE: Although accumulating evidence suggests the presence of microbleeds as a risk factor for intracerebral hemorrhage (ICH), little is known about its significance in anticoagulated patients. The aim of this study was to determine whether the presence of microbleeds is associated with recurrent hemorrhagic stroke in patients who had received warfarin following atrial fibrillation–associated cardioembolic infarction. MATERIALS AND METHODS: A total of 87 consecutive patients with acute recurrent stroke, including 15 patients with ICH and 72 patients with cerebral infarction, were enrolled in this study. International normalized ratios (INRs), vascular risk factors, and imaging characteristics, including microbleeds on T2*-weighted MR images and white matter hyperintensity (WMH) on T2-weighted MR images, were compared in the 2 groups. RESULTS: Microbleeds were noted more frequently in patients with ICH than in patients with cerebral infarction (86.7% versus 38.9%, P = .0007). The number of microbleeds was larger in patients with ICH than in patients with cerebral infarction (mean, 8.4 versus 2.1; P = .0001). INR was higher in patients with ICH than in patients with cerebral infarction (mean, 2.2 versus 1.4; P < .0001). The frequency of hypertension was higher in patients with ICH than in patients with cerebral infarction (86.7% versus 45.8%, P = .0039). Multivariate analysis revealed that the presence of cerebral microbleeds (odds ratio, 7.383; 95% confidence interval, 1.052–51.830) was associated with ICH independent of increased INR and hypertension. CONCLUSION: The presence of cerebral microbleeds may be an independent risk factor for warfarin-related ICH, but more study is needed because of strong confounding associations with elevated INR and hypertension.

LIF-free embryonic stem cell culture in simulated microgravity.

Background Leukemia inhibitory factor (LIF) is an indispensable factor for maintaining mouse embryonic stem (ES) cell pluripotency. A feeder layer and serum are also needed to maintain an undifferentiated state, however, such animal derived materials need to be eliminated for clinical applications. Therefore, a more reliable ES cell culture technique is required. Methodology/Principal Findings We cultured mouse ES cells in simulated microgravity using a 3D-clinostat. We used feeder-free and serum-free media without LIF. Conclusions/Significance Here we show that simulated microgravity allows novel LIF-free and animal derived material-free culture methods for mouse ES cells.

White matter lesions in the brain with frontotemporal lobar degeneration with motor neuron disease: TDP-43-immunopositive inclusions co-localize with p62, but not ubiquitin

Recently, TDP-43 was established as a major component of the ubiquitinated inclusions found in both amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration with motor neuron disease (FTLD-MND). However, differences in the underlying pathogenesis between ALS and FTLD-MND remain yet to be elucidated. Originally, TDP-43-immunopositive inclusions were found in neuronal cells and reported to be ubiquitinated. This study shows that TDP-43-positive inclusions were distributed throughout the subcortical white matter except for the occipital lobe in the FTLD-MND brain, but not in the ALS brain. TDP-43-positive inclusions were also prominent features of pathologically proven FTLD-MND cases (p-FTLD-MND) without history of apparent clinical cognitive decline. A substantial fraction of these inclusions was also p62-immunoreactive, and another noteworthy feature was that those inclusions did not stain positively for ubiquitin. Significant correlations between immunoreactivity for TDP-43 and p62 were observed, particularly in p-FTLD-MND (Pearson correlation coefficient, 0.976). Furthermore, TDP-43 extracted from white matter appeared to be uncleaved. These results indicate that pathological changes might take place within the white matter also in the brain with FTLD-MND, but in a different manner than within the gray matter.

Abundance of aspargynyl-hydroxylase FIH is regulated by Siah-1 under normoxic conditions

The activity of hypoxia-inducible factors-1alpha (HIF-1alpha) is regulated by two types of hydroxylases, prolyl-hydroxylase (PHD) and aspargynyl-hydroxylase factor inhibiting HIF-1alpha (FIH). Hydroxylation of HIF-1alpha by PHD and FIH causes proteasomal degradation and transcriptional inhibition of HIF-1alpha, respectively. Siah ubiquitin ligases regulate the abundance of PHD via targeting for proteasomal degradation. The present study investigated the role of Siah-1 in the regulation of FIH abundance under normoxic conditions. Immunohistochemical analysis of the rat brains revealed that both Siah-1 and FIH were widely distributed in the central nervous system including the cerebral cortex, the hippocampus, the striatum, the olfactory bulb, the putamen, the thalamus, the celleberum, and the brain stem. In the hippocampus, both Siah-1 and FIH predominantly expressed in neurons. Siah-1 and FIH localized mostly in the cytoplasm. In mammalian cells, FIH expression levels were increased in the presence of a proteasomal inhibitor MG132, suggesting that FIH is degraded by the ubiquitin-proteasome system. Immunoprecipitation assay and ubiquitination assay revealed that Siah-1 interacted with, and ubiquitinated FIH. Under normoxic conditions, Siah-1 facilitated degradation of FIH. On the other hand, when endogenous Siah-1 expression was suppressed using siRNA, FIH expression levels were increased, as compared to control. These results suggest that Siah-1 might play a role as a regulator of FIH abundance under normoxic conditions.

Simulated microgravity maintains the undifferentiated state and enhances the neural repair potential of bone marrow stromal cells.

Recently, regenerative medicine with bone marrow stromal cells (BMSCs) has gained significant attention for the treatment of central nervous system diseases. Here, we investigated the activity of BMSCs under simulated microgravity conditions. Mouse BMSCs (mBMSCs) were isolated from C57BL/6 mice and harvested in 1G condition. Subjects were divided into 4 groups: cultured under simulated microgravity and 1G condition in growth medium and neural differentiation medium. After 7 days of culture, the mBMSCs were used for morphological analysis, reverse transcription (RT)-polymerase chain reaction, immunostaining analysis, and grafting. Neural-induced mBMSCs cultured under 1G conditions exhibited neural differentiation, whereas those cultured under simulated microgravity did not. Moreover, under simulated microgravity conditions, mBMSCs could be cultured in an undifferentiated state. Next, we intravenously injected cells into a mouse model of cerebral contusion. Graft mBMSCs cultured under simulated microgravity exhibited greater survival in the damaged region, and the motor function of the grafted mice improved significantly. mBMSCs cultured under simulated microgravity expressed CXCR4 on their cell membrane. Our study indicates that culturing cells under simulated microgravity enhances their survival rate by maintaining an undifferentiated state of cells, making this a potentially attractive method for culturing donor cells to be used in grafting.

Positional relationship between recurrent intracerebral hemorrhage/lacunar infarction and previously detected microbleeds.

BACKGROUND AND PURPOSE: Although MBs, ICH, and LI are secondary to cerebral microangiopathy, it remains unclear whether the location of subsequent ICH/LI corresponds to the previous location of MBs. We performed this study to clarify the positional relationship between recurrent ICH/LI and previously detected MBs. MATERIALS AND METHODS: We evaluated patients with recurrent ICH/LI who had MBs, as shown on prior T2*-weighted MR imaging. We assessed retrospectively whether the location of recurrent ICH/LI corresponded to that of the prior MB. Patients with ICH were divided into the deep ICH group and the lobar ICH group, and the positional relationship between hematoma and previously detected MBs was evaluated. RESULTS: A total of 55 patients, including 34 with recurrent ICH and 21 with recurrent LI were evaluated. Although the location of the LI corresponded to prior MBs in only 1 patient (4.8%), the location of ICH corresponded to prior locations of MBs in 21 patients (61.8%) (OR, 32.3; 95% CI, 3.86–270.3; P < .001). Among the patients with ICH, the correspondence ratio was higher in the deep ICH group (19 of 24 patients, 79.2%) than in the lobar ICH group (2 of 10 patients, 20%) (OR, 15.2; 95% CI, 2.42–95.3; P < .002). CONCLUSIONS: The close positional association between recurrent ICH and prior MBs suggests that MBs represent hemorrhage-prone microangiopathy. In addition, different correspondence ratios between the deep ICH group and the lobar ICH group may be attributable to their different pathogenesis.

Synphilin-1 transgenic mice exhibit mild motor impairments

Synphilin-1 represents a cytoplasmic protein that interacts with alpha-synuclein and localizes close to synaptic vesicles. The interaction of synphilin-1 with several proteins involved in Parkinsons disease suggests that it might be involved in the pathogenesis of the disease. Nonetheless, the function of synphilin-1 remains unclear. In the present study, we generated transgenic mice expressing human synphilin-1 under the prion protein promoter. Synphilin-1 was widely expressed in neurons in the brain including the substantia nigra, where massive loss of dopamine neurons was not observed. In the transgenic mouse brain, synphilin-1 protein was polyubiquitinated, and partially insoluble. Although modified-SHIRPA revealed no significant difference in behavior and morphology, the reduced rotarod performance and step length were observed in transgenic mice as compared with non-transgenic littermates. Synphilin-1 might be involved in motor function, and its accumulation in the central nervous system can cause motor impairments.

The pathophysiology of prospective memory failure after diffuse axonal injury - Lesion-symptom analysis using diffusion tensor imaging

BackgroundProspective memory (PM) is one of the most important cognitive domains in everyday life. The neuronal basis of PM has been examined by a large number of neuroimaging and neuropsychological studies, and it has been suggested that several cerebral domains contribute to PM. For these activation studies, a constellation of experimental PM trials was developed and adopted to healthy subjects. In the present study, we used a widely used clinical PM assessment battery to determine the lesions attributable to PM failure, with the hypothesis that lesion-symptom analysis using diffusion tensor imaging (DTI) in subjects with diffuse axonal injury (DAI) can reveal the neuronal basis of PM in everyday life.ResultsFourteen DAI patients (age: range of 18-36, median 24) participated in this study. PM failure was scored in the range of 0-6 using three sub-tests of the Rivermead Behavioural Memory Test. The PM scores of DAI patients were in the range of 2-6 (median 4.5, inter-quartile range 2.25). The severity of axonal injury following DAI was examined using fractional anisotropy (FA), one of the DTI parameters, at voxel level in each subject. We then obtained clusters correlated with PM failure by conducting voxel-based regression analysis between FA values and PM scores. Three clusters exhibited significant positive correlation with PM score, the left parahippocampal gyrus, left inferior parietal lobe, and left anterior cingulate.ConclusionsThis is the first lesion-symptom study to reveal the neuronal basis of PM using DTI on subjects with DAI. Our findings suggest that the neuronal basis of PM is in the left parahippocampal gyrus, left inferior parietal lobe, and/or left anterior cingulate. These findings are similar to those of previous activation studies with loading experimental PM tasks.