Giant Intraosseous Meningioma Associated with Calvarial Hyperostosis and Subcutaneous Invasion: Case Reports and Literature Review.

Most meningiomas grow intracranially, and primary intraosseous meningioma is rarely reported. We present two rare surgical cases of giant intraosseous meningothelial meningioma. The first patient was a 35-year-old male with parietal skull deformity without neurological symptoms. Total resection was successful. The origin was the parasagittal intraosseous layer, and the superior sagittal sinus was partially opened. The second patient was a 20-year-old female with a slightly upward protrusion of the frontal skull without pain or neurological deficits. The lesion was totally resected, and the origin was the parasagittal intraosseous layer invading into the dura matter and subcutaneous layer. The clinical management of these cases presented a surgical challenge because of detachment and repair from venous sinuses. The current report provides surgical tips for such rare diseases and is a good reference for the future treatment of similar diseases.

Local field potentials identify features of cortico-hippocampal communication impacted by stroke and environmental enrichment therapy.

Objective. Cognitive and memory impairments are common sequelae after stroke, yet how middle cerebral artery (MCA) stroke chronically affects the neural activity of the hippocampus, a brain region critical for memory but remote from the stroke epicenter, is poorly understood. Environmental enrichment (EE) improves cognition following stroke; however, the electrophysiology that underlies this behavioral intervention is still elusive.Approach.We recorded extracellular local field potentials simultaneously from sensorimotor cortex and hippocampus in rats during urethane anesthesia following MCA occlusion and subsequent EE treatment.Main results.We found that MCA stroke significantly impacted the electrophysiology in the hippocampus, in particular it disrupted characteristics of sharp-wave associated ripples (SPW-Rs) altered brain state, and disrupted phase amplitude coupling (PAC) within the hippocampus and between the cortex and hippocampus. Importantly, we show that EE mitigates stroke-induced changes to SPW-R characteristics but does not restore hippocampal brain state or PAC.Significance.These results begin to uncover the complex interaction between cognitive deficit following stroke and EE treatment, providing a testbed to assess different strategies for therapeutics following stroke.

The effect of type 2 diabetes on CD36 expression and the uptake of oxLDL: Diabetes affects CD36 and oxLDL uptake.

We investigated whether type 2 diabetes mellitus (T2DM), a risk factor of stroke, affects the level of scavenger receptor CD36 and the uptake of its ligand, oxidized LDL (oxLDL); and whether pioglitazone, a drug that enhances CD36, promotes oxLDL uptake. Compared to normoglycemic db/+ mice, adult db/db mice showed a pronounced reduction in surface CD36 expression on myeloid cells from the blood, brain, and bone marrow as detected by flow cytometry, which correlated with elevated plasma soluble-CD36 as determined by ELISA. Increased CD36 expression was found in brain macrophages and microglia of both genotypes 7 days after ischemic stroke. In juvenile db/db mice, prior to obesity and hyperglycemia, only a mild reduction of surface CD36 was found in blood neutrophils, while all other myeloid cells showed no difference relative to the db/+ strain. In vivo, oral pioglitazone treatment for four weeks increased CD36 levels on myeloid cells in db/db mice. In vitro, uptake of oxLDL by bone marrow derived macrophages (BMDMs) of db/db mice was reduced relative to db/+ mice in normal glucose medium. OxLDL uptake inversely correlated with glucose levels in the medium in db/+ BMDMs. Furthermore, pioglitazone restored oxLDL uptake by BMDMs from db/db mice cultured in high glucose. Our data suggest that T2DM is associated with reduced CD36 on adult myeloid cells, and pioglitazone enhances CD36 expression in db/db cells. T2DM or high glucose reduces oxLDL uptake while pioglitazone enhances oxLDL uptake. Our findings provide new insight into the mechanism by which pioglitazone may be beneficial in the treatment of insulin resistance.

The impact of native leptomeningeal collateralization on rapid blood flow recruitment following ischemic stroke.

The leptomeningeal collateral status is an independent predictor of stroke outcome. By means of optical coherent tomography angiography to compare two mouse strains with different extent of native leptomeningeal collateralization, we determined the spatiotemporal dynamics of collateral flow and downstream hemodynamics following ischemic stroke. A robust recruitment of leptomeningeal collateral flow was detected immediately after middle cerebral artery (MCA) occlusion in C57BL/6 mice, with continued expansion over the course of seven days. In contrast, little collateral recruitment was seen in Balb/C mice during- and one day after MCAO, which coincided with a greater infarct size and worse functional outcome compared to C57BL/6, despite a slight improvement of cortical perfusion seven days after MCAO. Both strains of mice experienced a reduction of blood flow in the penetrating arterioles (PA) by more than 90% 30-min after dMCAO, although the decrease of PA flow was greater and the recovery was less in the Balb/C mice. Further, Balb/C mice also displayed a prolonged greater heterogeneity of capillary transit time after dMCAO in the MCA territory compared to C57BL/6 mice. Our data suggest that the extent of native leptomeningeal collaterals affects downstream hemodynamics with a long lasting impact in the microvascular bed after cortical stroke.

Intractable Hiccups as the Primary Symptom of a Perimedullary Arteriovenous Fistula at the Craniocervical Junction.

BACKGROUND: Hiccups are a well-known short-term phenomenon in daily life. If they persist or become intractable, they may be a primary symptom of a disease. Recent studies identified the medulla oblongata as the neuroanatomic center of the hiccup reflex arc. In previous cases, an isolated lesion at the dorsal side of the medulla oblongata induced intractable hiccups. CASE DESCRIPTION: We herein describe a patient with a perimedullary arteriovenous fistula (PMAVF) at the craniocervical junction who had intractable hiccups. A 70-year-old male presented with a 3-year history of intractable hiccups that continued for a few days every week. An initial examination failed to identify the underlying cause, and neither medicine nor self-treatment attenuated his symptoms. Intracranial T2-weighted magnetic resonance imaging showed a hyperintensity area within the dorsolateral medulla and flow voids along the dorsal side of the cervical spine. Angiography revealed PMAVF fed by the left C1 radiculomedullary artery. Obliteration of the fistula was performed, after which intractable hiccups had completely disappeared within 1 week. CONCLUSIONS: This is the first case report of PMAVF at the craniocervical junction presenting with intractable hiccups that suggested a lesion in the dorsal side of the medulla. The mechanisms underlying hiccups are also discussed.

Efficacy of intra-arterial indocyanine green angiography for the microsurgical treatment of dural arteriovenous fistula: A case report.

BACKGROUND: In this study, we report a case of dural arteriovenous fistula (dAVF) that was successfully treated using intra-arterial indocyanine green (IA-ICG) videoangiography during open surgery. Moreover, the findings of IA-ICG videoangiography were compared with those of intraoperative digital subtraction angiography (DSA). CASE DESCRIPTION: A 72-year-old male patient with a history of hypertension, hyperlipidemia, and thrombocytosis presented with generalized seizure. DSA revealed Cognard Type III dAVF in the superior wall of the left transverse sinus, which was fed by a single artery (the left occipital artery [OA]) and drained into a single vein (the left temporal cortical vein), without drainage into a venous sinus. Since transarterial embolization was considered challenging due to the tortuosity of the left OA, surgical interruption of the shunt was performed by craniotomy. After excising the feeding artery, we were unable to observed dAVF on intraoperative DSA. However, IA-ICG videoangiography revealed the remaining shunt, which was fed by the collateral route from the feeding artery. The shunting point and draining vein were then surgically resected to eliminate the shunt. The shunt was not observed during the second IA-ICG videoangiography conducted after resection. CONCLUSION: ICG videoangiography is a better method compared with DSA in terms of visualizing fine vascular lesions. In contrast to the typical intravenous administration, selective IA-ICG can be repeatedly injected at a minimal dose. IA-ICG is a useful intraoperative tool that can be used to evaluate the elimination of the dAVF.

Thoracic Dural Arteriovenous Fistula Presenting with Isolated Pseudobulbar Palsy Mimicking Brainstem Lesion.

BACKGROUND: Spinal dural arteriovenous fistulas (DAVFs) are usually associated with neurologic dysfunction adjacent to the shunt point; however, the symptoms are uncommon far from the site of the fistula. To our knowledge, this is the first report of a patient with rapidly progressive isolated pseudobulbar palsy because of thoracic DAVF. CASE DESCRIPTION: We report a patient with thoracic DAVF presenting with remote symptoms of brainstem congestion. The patient was a 36-year-old man who presented with a sudden history of vomiting, dysphagia, and flaccid weakness in the 4 limbs. Intracranial magnetic resonance (MR) imaging at a local hospital demonstrated T2 signal hyperintensity within the medulla, and he was referred to our hospital for a suspected brainstem lesion. However, cervical MR imaging revealed a dilated and tortuous perimedullary venous plexus, and spinal angiography revealed DAVF in T5-6 with a feeding artery from the intercostal artery. After obliteration of the fistula, the progression of the disease was stopped and the symptoms improved. CONCLUSIONS: Although rare, thoracic DAVFs may present symptoms resembling brainstem infarction. Prompt surgical intervention is necessary for patients with thoracic DAVF presenting with rapidly progressive pseudobulbar palsy.

Experimental cortical stroke induces aberrant increase of sharp-wave-associated ripples in the hippocampus and disrupts cortico-hippocampal communication.

The functional consequences of ischemic stroke in the remote brain regions are not well characterized. The current study sought to determine changes in hippocampal oscillatory activity that may underlie the cognitive impairment observed following distal middle cerebral artery occlusion (dMCAO) without causing hippocampal structural damage. Local field potentials were recorded from the dorsal hippocampus and cortex in urethane-anesthetized rats with multichannel silicon probes during dMCAO and reperfusion, or mild ischemia induced by bilateral common carotid artery occlusion (CCAO). Bilateral change of brain state was evidenced by reduced theta/delta amplitude ratio and shortened high theta duration following acute dMCAO but not CCAO. An aberrant increase in the occurrence of sharp-wave-associated ripples (150-250 Hz), crucial for memory consolidation, was only detected after dMCAO reperfusion, coinciding with an increased occurrence of high-frequency discharges (250-450 Hz). dMCAO also significantly affected the modulation of gamma amplitude in the cortex coupled to hippocampal theta phase, although both hippocampal theta and gamma power were temporarily decreased during dMCAO. Our results suggest that MCAO may disrupt the balance between excitatory and inhibitory circuits in the hippocampus and alter the function of cortico-hippocampal network, providing a novel insight in how cortical stroke affects function in remote brain regions.

Impaired Collateral Flow Compensation During Chronic Cerebral Hypoperfusion in the Type 2 Diabetic Mice.

BACKGROUND AND PURPOSE: The presence of collaterals is associated with a reduced risk of stroke and transient ischemic attack in patients with steno-occlusive carotid artery disease. Although metabolic syndrome negatively impacts collateral status, it is unclear whether and to what extent type 2 diabetes mellitus affects cerebral collateral flow regulation during hypoperfusion. METHODS: We examined the spatial and temporal changes of the leptomeningeal collateral flow and the flow dynamics of the penetrating arterioles in the distal middle cerebral artery and anterior cerebral artery branches over 2 weeks after unilateral common carotid artery occlusion (CCAO) using optical coherent tomography in db/+ and db/db mice. We also assessed the temporal adaptation of the circle of Willis after CCAO by measuring circle of Willis vessel diameters. RESULTS: After unilateral CCAO, db/db mice exhibited diminished leptomeningeal collateral flow compensation compared with db/+ mice, which coincided with a reduced dilation of distal anterior cerebral artery branches, leading to reduced flow not only in pial vessels but also in penetrating arterioles bordering the distal middle cerebral artery and anterior cerebral artery. However, no apparent cell death was detected in either strain of mice during the first week after CCAO. db/db mice also experienced a more severe early reduction in the vessel diameters of several ipsilateral main feeding arteries in the circle of Willis, in addition to a delayed post-CCAO adaptive response by 1 to 2 weeks, compared with db/+ mice. CONCLUSIONS: Type 2 diabetes mellitus is an additional risk factor for hemodynamic compromise during cerebral hypoperfusion, which may increase the severity and the risk of stroke or transient ischemic attack.

Perturbation of Brain Oscillations after Ischemic Stroke: A Potential Biomarker for Post-Stroke Function and Therapy.

Brain waves resonate from the generators of electrical current and propagate across brain regions with oscillation frequencies ranging from 0.05 to 500 Hz. The commonly observed oscillatory waves recorded by an electroencephalogram (EEG) in normal adult humans can be grouped into five main categories according to the frequency and amplitude, namely δ (1-4 Hz, 20-200 µV), θ (4-8 Hz, 10 µV), α (8-12 Hz, 20-200 µV), ß (12-30 Hz, 5-10 µV), and γ (30-80 Hz, low amplitude). Emerging evidence from experimental and human studies suggests that groups of function and behavior seem to be specifically associated with the presence of each oscillation band, although the complex relationship between oscillation frequency and function, as well as the interaction between brain oscillations, are far from clear. Changes of brain oscillation patterns have long been implicated in the diseases of the central nervous system including ischemic stroke, in which the reduction of cerebral blood flow as well as the progression of tissue damage have direct spatiotemporal effects on the power of several oscillatory bands and their interactions. This review summarizes the current knowledge in behavior and function associated with each brain oscillation, and also in the specific changes in brain electrical activities that correspond to the molecular events and functional alterations observed after experimental and human stroke. We provide the basis of the generations of brain oscillations and potential cellular and molecular mechanisms underlying stroke-induced perturbation. We will also discuss the implications of using brain oscillation patterns as biomarkers for the prediction of stroke outcome and therapeutic efficacy.

Impaired leptomeningeal collateral flow contributes to the poor outcome following experimental stroke in the Type 2 diabetic mice.

Collateral status is an independent predictor of stroke outcome. However, the spatiotemporal manner in which collateral flow maintains cerebral perfusion during cerebral ischemia is poorly understood. Diabetes exacerbates ischemic brain damage, although the impact of diabetes on collateral dynamics remains to be established. Using Doppler optical coherent tomography, a robust recruitment of leptomeningeal collateral flow was detected immediately after middle cerebral artery (MCA) occlusion in C57BL/6 mice, and it continued to grow over the course of 1 week. In contrast, an impairment of collateral recruitment was evident in the Type 2 diabetic db/db mice, which coincided with a worse stroke outcome compared with their normoglycemic counterpart db/+, despite their equally well-collateralized leptomeningeal anastomoses. Similar to the wild-type mice, both db/+ and db/db mice underwent collateral growth 7 d after MCA stroke, although db/db mice still exhibited significantly reduced retrograde flow into the MCA territory chronically. Acutely induced hyperglycemia in the db/+ mice did not impair collateral flow after stroke, suggesting that the state of hyperglycemia alone was not sufficient to impact collateral flow. Human albumin was efficacious in improving collateral flow and outcome after stroke in the db/db mice, enabling perfusion to proximal MCA territory that was usually not reached by retrograde flow from anterior cerebral artery without treatment. Our results suggest that the impaired collateral status contributes to the exacerbated ischemic injury in mice with Type 2 diabetes, and modulation of collateral flow has beneficial effects on stroke outcome among these subjects.

Collaterals: Implications in cerebral ischemic diseases and therapeutic interventions.

Despite the tremendous progress made in the treatment of cerebrovascular occlusive diseases, many patients suffering from ischemic brain injury still experience dismal outcomes. Although rehabilitation contributes to post-stroke functional recovery, there is no doubt that interventions that promote the restoration of blood supply are proven to minimize ischemic injury and improve recovery. In response to the acutely decreased blood perfusion during arterial occlusion, arteriogenesis, the compensation of blood flow through the collateral circulation during arterial obstructive diseases can act not only in a timely fashion but also much more efficiently compared to angiogenesis, the sprouting of new capillaries, and a mechanism occurring in a delayed fashion while increases the total resistance of the vascular bed of the affected territory. Interestingly, despite the vast differences between the two vascular remodeling mechanisms, some crucial growth factors and cytokines involved in angiogenesis are also required for arteriogenesis. Understanding the mechanisms underlying vascular remodeling after ischemic brain injury is a critical step towards the development of effective therapies for ischemic stroke. The present article will discuss our current views in vascular remodeling acutely after brain ischemia, namely arteriogenesis, and some relevant clinical therapies available on the horizon in augmenting collateral flow that hold promise in treating ischemic brain injury. This article is part of a Special Issue entitled SI: Cell Interactions In Stroke.

Consistent delayed unilateral neuronal death after modified transient focal cerebral ischemia in mice that mimics neuronal injury after transient global cerebral ischemia.

OBJECT: Numerous studies have attempted to reveal the pathophysiology of ischemic neuronal injury using a representative transient global cerebral ischemia (tGCI) model in rodents; however, most of them have used gerbil or rat models. Recent advances in transgene and gene-knockout technology have enabled the precise molecular mechanisms of ischemic brain injury to be investigated. Because the predominant species for the study of genetic mutations is the mouse, a representative mouse model of tGCI is of particular importance. However, simple mouse models of tGCI are less reproducible; therefore, a more complex process or longer duration of ischemia, which causes a high mortality rate, has been used in previous tGCI models in mice. In this study, the authors aimed to overcome these problems and attempted to produce consistent unilateral delayed hippocampal CA1 neuronal death in mice. METHODS: C57BL/6 mice were subjected to short-term unilateral cerebral ischemia using a 4-mm silicone-coated intraluminal suture to obstruct the origin of the posterior cerebral artery (PCA), and regional cerebral blood flow (rCBF) of the PCA territory was measured using laser speckle flowmetry. The mice were randomly assigned to groups of different ischemic durations and histologically evaluated at different time points after ischemia. The survival rate and neurological score of the group that experienced 15 minutes of ischemia were also evaluated. RESULTS: Consistent neuronal death was observed in the medial CA1 subregion 4 days after 15 minutes of ischemia in the group of mice with a reduction in rCBF of < 65% in the PCA territory during ischemia. Morphologically degenerated cells were mostly positive for terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling and cleaved caspase 3 staining 4 days after ischemia. The survival rates of the mice 24 hours (n = 24), 4 days (n = 15), and 7 days (n = 7) after being subjected to 15 minutes of ischemia were 95.8%, 100%, and 100%, respectively, and the mice had slight motor deficits. CONCLUSIONS: The authors established a model of delayed unilateral hippocampal neuronal death in C57BL/6 mice by inducing ischemia in the PCA territory using an intraluminal suture method and established inclusion criteria for PCAterritory rCBF monitored by laser speckle flowmetry. This model may be useful for investigating the precise molecular mechanisms of ischemic brain injury.

Increased vascular MMP-9 in mice lacking RNF213: moyamoya disease susceptibility gene.

Moyamoya disease (MMD) is a chronic occlusive cerebrovascular disease with unknown etiology. Recent genetic studies have identified RNF213 as an important susceptibility gene for MMD. To evaluate the role of RNF213 in vascular remodeling, RNF213 knockout mice (RNF213-/-) and their wild-type littermates (WT) were subjected to common carotid artery ligation to induce vascular hyperplasia. We examined the vascular expression of matrix metalloproteinase (MMP)-9, known to be increased in MMD. MMP-9 expression was significantly higher in RNF213-/- mice than in wild-type mice 1 and 7 days after common carotid artery ligation. The vascular wall was significantly thinner in RNF213-/- mice at 14 days. The increased vascular expression of MMP-9 and subsequent vascular wall thinning in RNF213-/- mice could reflect the early characteristic of MMD, consistent with the recently proposed constrictive remodeling theory.

Genetics and Biomarkers of Moyamoya Disease: Significance of RNF213 as a Susceptibility Gene.

Moyamoya disease is characterized by a progressive stenosis at the terminal portion of the internal carotid artery and an abnormal vascular network at the base of the brain. Although its etiology is still unknown, recent genome-wide and locus-specific association studies identified RNF213 as an important susceptibility gene of moyamoya disease among East Asian population. A polymorphism in c.14576G>A in RNF213 was identified in 95% of familial patients with moyamoya disease and 79% of sporadic cases, and patients having this polymorphism were found to have significantly earlier disease onset and a more severe form of moyamoya disease, such as the presentation of cerebral infarction and posterior cerebral artery stenosis. The exact mechanism by which the RNF213 abnormality relates to moyamoya disease remains unknown, while recent reports using genetically engineered mice lacking RNF213 by homologous recombination provide new insight for the pathogenesis of this rare entity. Regarding biomarkers of moyamoya disease, moyamoya disease is characterized by an increased expression of angiogenic factors and pro-inflammatory molecules such as vascular endothelial growth factors and matrix metalloproteinase-9, which may partly explain its clinical manifestations of the pathologic angiogenesis, spontaneous hemorrhage, and higher incidence of cerebral hyperperfusion after revascularization surgery. More recently, blockade of these pro-inflammatory molecules during perioperative period is attempted to reduce the potential risk of surgical complication including cerebral hyperperfusion syndrome. In this review article, we focus on the genetics and biomarkers of moyamoya disease, and sought to discuss their clinical implication.

Temporal profile of the vascular anatomy evaluated by 9.4-T magnetic resonance angiography and histopathological analysis in mice lacking RNF213: a susceptibility gene for moyamoya disease.

Moyamoya disease (MMD) is a chronic occlusive cerebrovascular disease with unknown etiology. Recent genome-wide and locus-specific association studies identified RNF213 as an important MMD susceptibility gene. However, the exact mechanism by which an abnormality in RNF213 leads to MMD is unknown. To evaluate the role of RNF213 in the etiology of MMD, we generated RNF213-deficient mice (RNF213-/-) by deleting exon 32 of RNF213 by the Cre-lox system, and investigated whether they developed MMD. The temporal profile of cervical/intracranial arteries was evaluated by 9.4-T magnetic resonance angiography (MRA). The anatomy of the circle of Willis was analyzed by a trans-cardiac injection of carbon black dye. The common carotid arteries (CCA) were sectioned and the arterial wall thickness/thinness was evaluated by Elastica-Masson staining before and after CCA ligation, which selectively induced vascular hyperplasia. As a result, RNF213-/- grew normally, and no significant difference was observed in MRA findings, the anatomy of the circle of Willis, or vascular wall thickness/thinness between RNF-/- and wild-type littermates (Wt.) under normal conditions until 64 weeks of age. However, Elastica-Masson staining demonstrated that both the intima and medial layer were significantly thinner after CCA ligation in RNF213-/- than in Wt. after 14 days (P<0.01). In conclusion, mice lacking the RNF213 gene did not spontaneously develop MMD, indicating that a functional loss of RNF213 did not sufficiently induce MMD. Suppression of vascular remodeling in RNF213-/- requires further examination to clarify the role of RNF213.

Cushing's disease associated with unruptured large internal carotid artery aneurysm. Case report.

A 40-year-old woman with Cushing's disease presented with hypertensive cerebral hemorrhage. Neuroimaging detected an unruptured large intracavernous aneurysm, which projected beyond the midline, and thin crescent-shaped adenoma along the aneurysm wall. The aneurysm was treated with endovascular tight packing with coils. Transsphenoidal adenomectomy was then safely performed. The signs of Cushing's disease were resolved, and she was discharged without deficits. The first line therapy for Cushing's disease is transsphenoidal adenomectomy. However, the therapeutic strategy and optimal timing of treatment are unclear for Cushing's disease with large intracavernous aneurysm. The present case shows that transsphenoidal surgery was safely possible with minimal invasiveness after embolization of the intracavernous aneurysm.

Neuroendoscopic management of symptomatic septum pellucidum cavum vergae cyst using a high-definition flexible endoscopic system.

A 24-year-old man, who had an asymptomatic septum pellucidum cyst incidentally found one year previously, presented with severe headache and right abducens nerve palsy caused by expansion of the midline cyst. Preoperative magnetic resonance (MR) imaging revealed obstructive hydrocephalus due to the enlarged midline cyst. Neuroendoscopic fenestration of the septum pellucidum cyst was successfully performed via a right frontal approach using a high-resolution flexible neuroendoscopic system without complication. Communication between the cyst cavity and bilateral lateral ventricles was constructed via a single trajectory. The entire inner cyst wall could be inspected from the cyst cavity by manipulating the flexible neuroendoscopic system, which excluded the presence of neoplasm. His symptoms were completely relieved after surgery, and postoperative MR imaging showed significant improvement of hydrocephalus and shrinkage of the midline cyst. Septum pellucidum cavum vergae cyst may expand and become symptomatic, so fenestration using a flexible neuroendoscope system may be the optimal method for constructing communication to the bilateral lateral ventricles with minimal invasion.