Nobutaka Horie

Melatonin influences the proliferative and differentiative activity of neural stem cells

Abstract:  Though melatonin has a wide variety of biological functions, its effects on the neural stem cells (NSCs) is still unknown. In this study, we examined the effects of melatonin at either physiological (0.01–10 nm) or pharmacological concentrations (1–100 μm) on the proliferation and neural and astroglial differentiation of NSCs derived from the mouse embryo striatum using an in vitro culture system. We found that melatonin at pharmacological concentrations, but not at physiological concentrations, suppressed epidermal growth factor (EGF)‐stimulated NSC proliferation (increment of viable cells, DNA synthesis and neurosphere formation) in a concentration‐dependent manner. Furthermore, treatment with melatonin at a pharmacological concentration during the proliferation period facilitated 1% FBS‐induced neural differentiation of NSCs without affecting the astroglial differentiation. In contrast, the treatment with melatonin at pharmacological concentrations during the differentiation period decreased the neural differentiation of the NSCs. As with melatonin, MCI‐186, an antioxidant, suppressed EGF‐stimulated NSC proliferation and facilitated the subsequent neural differentiation of NSCs. These results suggest that melatonin exerts potent modulatory effects on NSC functions including the suppression of the proliferation and facilitation of neuronal differentiation, likely via its antioxidant activity. As neurogenesis is thought to play an important role in ameliorating the deficit in neurodegenerative diseases, melatonin might be beneficially used for the treatment diseases such as cerebral infarction.

Impact of clipping versus coiling on postoperative hemodynamics and pulmonary edema after subarachnoid hemorrhage.

Volume management is critical for assessment of cerebral vasospasm after aneurysmal subarachnoid hemorrhage (SAH). This multicenter prospective cohort study compared the impact of surgical clipping versus endovascular coiling on postoperative hemodynamics and pulmonary edema in patients with SAH. Hemodynamic parameters were measured for 14 days using a transpulmonary thermodilution system. The study included 202 patients, including 160 who underwent clipping and 42 who underwent coiling. There were no differences in global ejection fraction (GEF), cardiac index, systemic vascular resistance index, or global end-diastolic volume index between the clipping and coiling groups in the early period. However, extravascular lung water index (EVLWI) and pulmonary vascular permeability index (PVPI) were significantly higher in the clipping group in the vasospasm period. Postoperative C-reactive protein (CRP) level was higher in the clipping group and was significantly correlated with postoperative brain natriuretic peptide level. Multivariate analysis found that PVPI and GEF were independently associated with high EVLWI in the early period, suggesting cardiogenic edema, and that CRP and PVPI, but not GEF, were independently associated with high EVLWI in the vasospasm period, suggesting noncardiogenic edema. In conclusion, clipping affects postoperative CRP level and may thereby increase noncardiogenic pulmonary edema in the vasospasm period. His trial is registered with University Hospital Medical Information Network UMIN000003794.

Intra-arterial Cell Transplantation Provides Timing-Dependent Cell Distribution and Functional Recovery After Stroke

Background and Purpose— Intra-arterial cell transplantation offers a novel therapeutic strategy for stroke; however, it remains unclear how the timing of cell administration affects cell distribution, brain repair processes, and functional recovery. Here, we investigate the hypothesis that the timing of cell transplantation changes the behavior of the cell graft and the host environment in a way that affects functional recovery. Methods— Rats received human mesenchymal stem cells via the internal carotid artery at 1, 4, or 7 days (D1, D4, or D7) after middle cerebral artery occlusion and reperfusion. Animals were euthanized at various time points to assess cell distribution, infiltration of activated microglia, expression of brain-derived neurotrophic factor, reactive astrocytes, angiogenesis, and functional recovery. Results— Human mesenchymal stem cells were widely distributed both in the peri-infarct and core in D1, and dominantly in the peri-infarct in D4. Very few cells were observed on D7. At day 7 poststroke, microglia activation was significantly suppressed in both the peri-infarct and core in D1, and predominantly in the peri-infarct in D4. At day 21 poststroke, brain-derived neurotrophic factor was widely distributed throughout the peri-infarct in D1 and D4, along with many reactive astrocytes and considerable angiogenesis. Motor function improved earlier in D1 and later in D4, but no recovery was obtained in D7. Conclusions— Our results indicate that intra-arterial cell transplantation provides timing-dependent cell distribution and poststroke functional recovery via a combination of neuroprotection, reactive astrocyte enhancement, and angiogenesis.

Efficacy of DynaCT Digital Angiography in the Detection of the Fistulous Point of Dural Arteriovenous Fistulas

BACKGROUND AND PURPOSE: Identifying the precise hemodynamic features, including the fistulous point, is essential for treatments of dural arteriovenous fistulas (DAVFs). This study illustrates the efficacy of DynaCT digital angiograms obtained from a 3D C-arm CT to directly visualize the location of the fistulous points in DAVFs. MATERIALS AND METHODS: This retrospective study observed 14 consecutive patients with DAVFs, which included 7 cavernous sinuses, 4 transverse-sigmoid sinuses, 2 convexity-superior sagittal sinuses, and 1 tentorial sinus. In the assessment of the practical applicability for the diagnosis of DAVFs, images obtained from 2D digital subtraction angiography (DSA) and DynaCT were comparatively evaluated. RESULTS: In all patients, DynaCT digital angiography could clearly demonstrate the feeding arteries, the fistulous points, and the draining veins. Significant anatomic landmarks for the fistulous points with relationships to osseous structures were also provided. Compared with 2D DSA, DynaCT digital angiograms demonstrated 12 additional findings in 8 patients (57%), including the detection of the fistulous points (n = 7), the feeders (n = 1), the retrograde leptomeningeal drainage (n = 1), the draining veins (n = 1), and the venous anomaly (n = 2). CONCLUSIONS: In comparison with 2D DSA, DynaCT may provide more detailed information to evaluate DAVFs. DynaCT digital angiograms have a high contrast and isotropic spatial resolution, allowing a reliable visualization of small vessels and fine osseous structures. Such detailed information, especially for the location of the fistulous points, could be very useful for either the endovascular or the surgical treatments of DAVFs.

An epidemiological survey of moyamoya disease, unilateral moyamoya disease and quasi-moyamoya disease in Japan

OBJECTIVES Moyamoya disease (MMD) is a unique occlusive disease of the bilateral internal carotid arteries in which, compensation for occlusion results in an enrichment of collateral arteries at the base of the brain. However, the epidemiology of unilateral MMD (typical angiographic evidence of MMD unilaterally with equivocal contralateral findings), and quasi-MMD (MMD present with inherited or acquired disorders) is poorly known. Here, a nationwide epidemiological survey was conducted to estimate the total numbers of patients, the annual incidence rates and prevalences of MMD, unilateral MMD and quasi-MMD in Japan. PATIENTS AND METHODS The neurosurgery, neurology and pediatrics departments that were listed in Japanese resident training programs were recruited to participate in this survey. Questionnaires were directly mailed to 2998 departments in February 2006. RESULTS A total of 1183 departments replied to the questionnaire (39.5% response rate). It was estimated that there were 6670.9 MMD patients, 840.5 unilateral MMD patients and 430.4 quasi-MMD patients in Japan. The annual incidence rates of MMD, unilateral MMD and quasi-MMD are 1.13, 0.23 and 0.11/100,000, respectively, and the prevalences are 5.22, 0.66 and 0.34/100,000, respectively. These patients were mainly treated by neurosurgeons. An estimated total of 929.1 surgical interventions are performed in Japan annually. CONCLUSION This nationwide study reports the current epidemiologic status of MMD, unilateral MMD and quasi-MMD in Japan.

Significance of the Hemorrhagic Site for Recurrent Bleeding: Prespecified Analysis in the Japan Adult Moyamoya Trial

Background and Purpose— The primary results of the Japan Adult Moyamoya Trial revealed the statistically marginal superiority of bypass surgery over medical treatment alone in preventing rebleeding in moyamoya disease. The purpose of this analysis is to test the prespecified subgroup hypothesis that the natural course and surgical effects vary depending on the hemorrhagic site at onset. Methods— The hemorrhagic site, classified as either anterior or posterior, was the only stratifying variable for randomization. Statistical analyses were focused on the assessment of effect modification according to the hemorrhagic site and were based on tests of interaction. Results— Of 42 surgically treated patients, 24 were classified as anterior hemorrhage and 18 as posterior hemorrhage; of 38 medically treated patients, 21 were classified as anterior and 17 as posterior. The hazard ratio of the primary end points (all adverse events) for the surgical group relative to the nonsurgical group was 0.07 (95% confidence interval, 0.01–0.55) for the posterior group, as compared with 1.62 (95% confidence interval, 0.39–6.79) for the anterior group (P=0.013 for interaction). Analysis within the nonsurgical group revealed that the incidence of the primary end point was significantly higher in the posterior group than in the anterior group (17.1% per year versus 3.0% per year; hazard ratio, 5.83; 95% confidence interval, 1.60–21.27). Conclusions— Careful interpretation of the results suggests that patients with posterior hemorrhage are at higher risk of rebleeding and accrue greater benefit from surgery, subject to verification in further studies. Clinical Trial Registration— URL: http://www.umin.ac.jp/ctr/index.htm. Unique identifier: C000000166.

Incidence and clinical features of symptomatic cerebral hyperperfusion syndrome after vascular reconstruction.

BACKGROUND Vascular reconstructions are the established treatment for ischemic cerebrovascular disease. Cerebral hyperperfusion syndrome (CHS) is occasionally seen after vascular reconstruction and manifest clinical symptoms. The purpose of this study is to investigate the incidence and clinical features of CHS after vascular reconstruction. METHODS A total of 144 patients with ischemic cerebrovascular disease (53 carotid endarterectomy [CEA] for carotid artery stenosis, 48 carotid artery stenting [CAS] for carotid artery stenosis, 20 bypass surgery for atherosclerotic cerebrovascular disease, 40 bypass surgery for moyamoya disease [MMD]) underwent vascular reconstruction. Patients were examined neurologically and radiologically, including computed tomography, magnetic resonance imaging, and single-photon-emission computed tomography, and then CHS was evaluated. RESULTS CHS developed in 1 (1.9%) CEA, 1 (2.1%) CAS, 1 (5.0%) bypass surgery for atherosclerotic cerebrovascular disease, and 6 (15.0%) bypass surgery for MMD. The incidence of CHS was significantly higher in patients with MMD. Aged patients and impairment of cerebrovascular reserve were correlated with CHS. Patients manifested disorientation after CEA and complained of headache after CAS. Diffuse hemispheric hyperperfusion was detected by single-photon-emission computed tomography. However, MMD patients manifested focal neurologic deficit, focal cerebral edema, and increased regional cerebral blood flow around vascular anastomosis. These patients were treated with blood pressure control and administration of free radical scavengers, and recovered without permanent deficits. CONCLUSIONS The incidence of CHS is significantly higher in patients with MMD and results in vasogenic edema visible on magnetic resonance imaging.

Assessment of Carotid Plaque Stability Based on the Dynamic Enhancement Pattern in Plaque Components With Multidetector CT Angiography

Background and Purpose— Recent studies have investigated plaque morphology to determine patients who are at high risk of carotid atherosclerosis. In this study, we investigated whether a difference in dynamic enhancement pattern in plaque components could be useful to assess plaque stability with multidetector CT angiography. Methods— Fifty-nine lesions with moderate to severe carotid atherosclerosis in 51 patients (33 symptomatic, 18 asymptomatic) were consecutively included. Early- and delayed-phase images were obtained in 3 equivalent axial slices with multidetector CT angiography. Hounsfield units (HU) in the early phase were subtracted from those in the delayed phase in plaques (&Dgr;HU) and compared with clinical features, MRI-based plaque characteristics, and histological findings with 20 surgical specimens acquired from carotid endarterectomy. Results— The &Dgr;HU was significantly higher in asymptomatic than that in symptomatic presentation (P=0.02). With MRI, a higher &Dgr;HU was negatively correlated with signal intensity on T1-weighted imaging (r=−0.56, P<0.0001). Histology confirmed that &Dgr;HU was positively correlated with fibrous tissue (r=0.67, P=0.001) and negatively correlated with a lipid-rich necrotic core with hemorrhage (r=−0.70, P<0.001). Moreover, less neovascularization and inflammation was found in plaques with a higher &Dgr;HU. Conclusions— Delayed-phase images provide information regarding the dynamic change in contrast media from the early arterial phase. An increase in HU from the early phase on multidetector CT angiography indicates plaque stability with more fibrous tissue and a less lipid-rich necrotic core, intraplaque hemorrhage, and neovascularization.

Detection of blood blister-like aneurysm and intramural hematoma with high-resolution magnetic resonance imaging.

Blood blister-like aneurysms (BBAs) tend to have a more precipitous clinical course, enlarging rapidly and rebleeding frequently. Nevertheless, they often present a diagnostic challenge because of the characteristic morphological features of a wide neck and shallow outpouching of the medial wall. The authors present the case of a 34-year-old woman who suffered a subarachnoid hemorrhage whose cause could not be determined on the initial imaging with digital subtraction (DS) angiography and CT angiography. Interestingly, MR imaging studies obtained on the 7th day revealed an intramural hematoma on the dorsal wall of the left internal carotid artery, which helped in the diagnosis of BBA on the third DS angiography study obtained on the 8th day, and in the surgical intervention on the 10th day. This case supports the hypothesis that focal dissection contributes to the formation of BBAs. Use of MR imaging in the subacute stage, in addition to DS and CT angiography, might be helpful in the diagnosis of BBAs.

Lowered glucose suppressed the proliferation and increased the differentiation of murine neural stem cells in vitro

Cerebral ischemia is known to activate endogenous neural stem cells (NSCs), but its mechanisms remain unknown. Since lowered glucose supply seems to mediate ischemic actions, we examined the effect of low glucose on NSC activities in vitro. Low glucose applied during the proliferation period diminished EGF‐induced proliferation of NSCs without affecting subsequent differentiation, but low glucose directly exposed during the differentiation period facilitated the differentiation of NSCs into neurons and astrocytes. These findings suggest that low glucose facilitated NSC differentiation, but it diminished NSC proliferation. Moreover, the effect of low glucose may be dependent on the timing of application.