An imbalance between RAGE/MR/HMGB1 and ATP1α3 is associated with infammatory changes in rat brain harboring cerebral aneurysms prone to rupture

An aneurysmal subarachnoid hemorrhage is a devastating event. To establish an effective therapeutic strategy, its pathogenesis must be clarified, particularly the pathophysiology of brain harboring intracranial aneurysms (IAs). To elucidate the pathology in brain harboring IAs, we examined the significance of the receptor for advanced glycation end-products (RAGE)/mineralocorticoid receptor (MR) pathway and Na/K-ATPase (ATP1α3). Ten-week-old female rats were subjected to oophorectomy as well as hypertension and hemodynamic changes to induce IAs, and were fed a high-salt diet. Brain damage in these rats was assessed by inflammatory changes in comparison to sham-operated rats fed a standard diet. Six weeks after IA induction (n = 30), irregular morphological changes, i.e., an enlarged vessel diameter and vascular wall, were observed in all of the left posterior cerebral arteries (Lt PCAs) prone to rupture. Approximately 20% of rats had ruptured IAs within 6 weeks. In brain harboring unruptured IAs at the PCA, the mRNA levels of RAGE and MR were higher, and that of ATP1α3 was lower than those in the sham-operated rats (p < 0.05, each). Immunohistochemically, elevated expression of RAGE and MR, and decreased expression of ATP1α3 were observed in the brain parenchyma adjacent to the Lt PCA, resulting in increased Iba-1 and S100B expression that reflected the inflammatory changes. There was no difference between the unruptured and ruptured aneurysm rat groups. Treatment with the MR antagonist esaxerenone abrogated these changes, and led to cerebral and vascular normalization and prolonged subarachnoid hemorrhage-free survival (p < 0.05). Regulation of the imbalance between the RAGE/MR pathway and ATP1α3 may help attenuate the damage in brain harboring IAs, and further studies are warranted to clarify the significance of the down-regulation of the MR/RAGE pathway and the up-regulation of ATP1α3 for attenuating the pathological changes in brain harboring IAs.


Activation of the NLRP3/IL-1β/MMP-9 pathway and intracranial aneurysm rupture associated with the depletion of ERα and Sirt1 in oophorectomized rats

Subarachnoid hemorrhage (SAH) due to intracranial aneurysm (IA) rupture is often a devastating event. Since the incidence of SAH increases especially in menopause, it is crucial to clarify the detailed pathogenesis of these events. The activation of vascular nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3) inflammasomes has been studied in ischemic stroke and cardiovascular disease. However, the role of NLRP3 in IA rupture still needs to be explained. The authors sought to test their hypothesis that, under estrogen-deficient conditions, activation of NLRP3 inflammasomes via downregulation of the estrogen receptor (ER) facilitates IA rupture. Ten-week-old female Sprague Dawley rats with and without oophorectomy were subjected to hemodynamic changes and hypertension (OVX+/HT and OVX-/HT, respectively) and fed a high-salt diet. Separately, using human brain endothelial cells (HBECs) and human brain smooth muscle cells (HBSMCs), the authors tested the effect of NLRP3 under estrogen-free conditions and in the presence of estradiol or of ER agonists. In OVX+/HT rats, the frequency of IA rupture was significantly higher than in OVX-/HT rats (p = 0.03). In the left posterior cerebral artery prone to rupture in OVX+/HT rats, the levels of the mRNAs encoding ERα and Sirt1, but not of that encoding ERβ, were decreased, and the levels of the mRNAs encoding NLRP3, interleukin-1β (IL-1β), and matrix metalloproteinase 9 (MMP-9) were elevated. Immunohistochemical analysis demonstrated that the expression profiles of these proteins correlated with their mRNA levels. Treatment with an ER modulator, bazedoxifene, normalized the expression profiles of these proteins and improved SAH-free survival. In HBECs and HBSMCs under estrogen-free conditions, the depletion of ERα and Sirt1 and the accumulation of NLRP3 were counteracted by exposure to estradiol or to an ERα agonist but not to an ERβ agonist. To the authors' knowledge, this work represents the first demonstration that, in an aneurysm model under estrogen-deficient conditions, the depletion of ERα and Sirt1 may contribute to activation of the NLRP3/IL-1β/MMP-9 pathway, facilitating the rupture of IAs in the estrogen-deficient rat IA rupture model.


Could clazosentan, first approved in Japan, improve neurological prognosis after subarachnoid hemorrhage in combination with modified water-electrolyte management?


Seizure types associated with negative arterial spin labeling and positive diffusion-weighted imaging on peri-ictal magnetic resonance imaging

Arterial spin labeling (ASL) and diffusion-weighted imaging (DWI) are useful for assessing hyperperfusion and cytotoxic edema, respectively, caused by acute seizures. This study investigated the clinical characteristics associated with normal ASL findings and DWI abnormalities in patients with acute seizures. Overall, 41 patients with ASL and DWI images that were obtained within 48 h of focal onset seizure diagnosis, due to epilepsy or acute symptomatic seizures, were divided into groups based on initial ASL findings (ASL-negative vs. ASL-positive), and DWI abnormalities (DWI-negative vs. DWI-positive). The diagnosis was made based on seizure semiology, electroencephalography, and conventional imaging modalities. ASL and DWI abnormalities were based on visual assessment. Of the 41 patients, eight (19.5%) displayed normal ASL findings. The proportion of patients with focal aware seizures (FAS) was significantly higher among ASL-negative patients (62.5%) than that in ASL-positive patients (15.2%); the proportion of patients with focal impaired awareness seizures (FIAS) was significantly lower among ASL-negative patients (12.5%) than that among ASL-positive patients (57.6%). Hyperintensity findings on DWI were observed in 12 patients (29.3%, DWI-positive). The proportion of patients with FIAS was significantly higher among DWI-positive patients (75.0%) than that among DWI-negative patients (37.9%). Multivariate analysis revealed that FAS and FIAS were associated with normal ASL findings (odds ratio [OR]: 21.37, P = 0.010) and DWI abnormalities (OR = 6.11, P = 0.028). A diagnosis of seizures should not be excluded based on normal ASL findings, especially in patients with FAS. FIAS may be a risk factor for neuronal damage caused by seizure activity.


Chronic subdural hematoma associated with dural metastasis leads to early recurrence and death: A single-institute, retrospective cohort study


Involvement of Neutrophil Extracellular Traps in Cerebral Arteriovenous Malformations

Cerebral arteriovenous malformations (cAVMs) represent tangles of abnormal vasculature without intervening capillaries. High-pressure vascular channels due to abnormal arterial and venous shunts can lead to rupture. Multiple pathways are involved in the pathobiology of cAVMs including inflammation and genetic factors such as KRAS mutations. Neutrophil release of nuclear chromatin, known as neutrophil extracellular traps (NETs), plays a multifunctional role in infection, inflammation, thrombosis, intracranial aneurysms, and tumor progression. However, the relationship between NETs and the pathobiology of cAVMs remains unknown. We tested whether NETs play a role in the pathobiology of cAVMs. We analyzed samples from patients who had undergone surgery for cAVM and immunohistochemically investigated expression of citrullinated histone H3 (CitH3) as a marker of NETs. CitH3 expression was compared among samples from cAVM patients, epilepsy patients, and normal human brain tissue. Expressions of thrombotic and inflammatory markers were also examined immunohistochemically in samples from cAVM patients. Expression of CitH3 derived from neutrophils was observed intravascularly in all cAVM samples but not other samples. Nidi of AVMs showed migration of many Iba-I-positive cells adjacent to the endothelium and endothelial COX2 expression, accompanied by expression of IL-6 and IL-8 in the endothelium and intravascular neutrophils. Unexpectedly, expression of CitH3 was not necessarily localized to the vascular wall and thrombus. Our results offer the first evidence of intravascular expression of NETs, which might be associated with vascular inflammation in cAVMs.


Coil embolization with overlapping horizontal low-profile stents to treat a giant thrombosed fetal posterior cerebral aneurysm using contralateral approach through anterior communicating artery: Case report.

The treatment of internal carotid artery (ICA) - posterior communicating artery aneurysms (ICPC aneurysms) is challenging when a fetal posterior cerebral artery (PCA) arises from the saccular neck. This complex angioarchitecture renders endovascular approaches difficult. Giant thrombosed IC-PC aneurysms are also hard to treat by endovascular coiling because its flow-diversion effect is insufficient. We report the first case of a ruptured giant thrombosed IC-PC aneurysm associated with a fetal PCA that was successfully treated by coil embolization with retrograde overlap horizontal stenting using low-profile stents introduced through the contralateral ICA. The aneurysm was completely occluded and follow-up MRI scans demonstrated the reduction of the aneurysmal size. Our technique is advantageous because low-profile stents can be used to treat lesions not accessible with flow-diverter stents due their presence in complex angioarchitectures, and overlap stenting may have flow-diversion effects that can result in the complete occlusion of giant thrombosed aneurysms.


Disequilibrium of Plasma Protease/Anti-Protease Due to Severe Periodontal Disease Contributes to Human Subarachnoid Hemorrhage


Action observation treatment improves gait ability in subacute to convalescent stroke patients.

The aim of this study was to investigate the effects of action observation treatment (AOT) on gait ability in patients with subacute to convalescent stroke. Sixteen patients with subacute stroke were divided into a control group (n = 8) and AOT group (n = 8) when admitted to the convalescent ward. The control group received a conventional rehabilitation only. In addition to conventional rehabilitation, the AOT received AOT for 3 months (30 min per day 5 times per week). The AOT involved observing the action of another subject in a comfortable gait situation from the front, sides, and back via video and conducting the actual action. All participants were assessed during the main-assessment period, which included a baseline (i.e., when admitted to the convalescent ward) and 1, 2, and 3 months after baseline. The sub-assessment period at 2 and 3 months after baseline was conducted with participants who could walk independently. The main outcomes of the main-assessment and sub-assessment periods were Functional Ambulation Classification (FAC) and the 10-m walk test (10MWT), respectively. With respect to the FAC, we used a split plot design analysis of covariance to test the interaction between assessment time and group. There was no significant interaction between assessment time and group in FAC. However, a significant improvement of the 10MWT in the sub-assessment period was observed in the AOT group, but not the control group. Our results indicate that AOT may be an effective therapy for patients with subacute to convalescent stroke who can walk independently.


Time-dependent and site-dependent morphological changes in rupture-prone arteries: ovariectomized rat intracranial aneurysm model

The pathogenesis of intracranial aneurysm rupture remains unclear. Because it is difficult to study the time course of human aneurysms and most unruptured aneurysms are stable, animal models are used to investigate the characteristics of intracranial aneurysms. The authors have newly established a rat intracranial aneurysm rupture model that features site-specific ruptured and unruptured aneurysms. In the present study the authors examined the time course of changes in the vascular morphology to clarify the mechanisms leading to rupture. Ten-week-old female Sprague-Dawley rats were subjected to hemodynamic changes, hypertension, and ovariectomy. Morphological changes in rupture-prone intracranial arteries were examined under a scanning electron microscope and the association with vascular degradation molecules was investigated. At 2-6 weeks after aneurysm induction, morphological changes and rupture were mainly observed at the posterior cerebral artery; at 7-12 weeks they were seen at the anterior Willis circle including the anterior communicating artery. No aneurysms at the anterior cerebral artery-olfactory artery bifurcation ruptured, suggesting that the inception of morphological changes is site dependent. On week 6, the messenger RNA level of matrix metalloproteinase-9, interleukin-1β, and the ratio of matrix metalloproteinase-9 to the tissue inhibitor of metalloproteinase-2 was significantly higher at the posterior cerebral artery, but not at the anterior communicating artery, of rats with aneurysms than in sham-operated rats. These findings suggest that aneurysm rupture is attributable to significant morphological changes and an increase in degradation molecules. Time-dependent and site-dependent morphological changes and the level of degradation molecules may be indicative of the vulnerability of aneurysms to rupture.


Activation of mirror neuron system during gait observation in sub-acute stroke patients and healthy persons.

The observation of walking improves gait ability in chronic stroke survivors. It has also been suggested that activation of the mirror neuron system contributes to this effect. However, activation of the mirror neuron system during gait observation has not yet been assessed in sub-acute stroke patients. The objective of this study was to clarify the activation of mirror neuron system during gait observation in sub-acute stroke patients and healthy persons. In this study, we sequentially enrolled five sub-acute stroke patients who had undergone gait training and nine healthy persons. We used fMRI to detect neuronal activation during gait observation. During the observation period in the stroke group, neural activity in the left inferior parietal lobule, right and left inferior frontal gyrus was significantly higher than during the rest period. In the healthy group, neural activity in the left inferior parietal lobule, left inferior frontal gyrus, left middle frontal gyrus, left superior temporal lobule and right and left middle temporal gyrus was significantly higher than during the rest period. The results indicate that the mirror neuron system was activated during gait observation in sub-acute stroke patients who had undergone gait training and also in healthy persons. Our findings suggest that gait observation treatment may provide a promising therapeutic strategy in sub-acute stroke patients who have experienced gait training.


Treatment of Unruptured Cerebral Aneurysms with the Mineralocorticoid Receptor Blocker Eplerenone-Pilot Study.

Currently there are no pharmacological therapies for patients with unruptured cerebral aneurysms. Elsewhere we showed that the mineralocorticoid receptor antagonist eplerenone prevented the formation of cerebral aneurysms in our ovariectomized hypertensive aneurysm rat model. The current pilot study evaluated whether it can be used to prevent the growth and rupture of cerebral aneurysms in hypertensive patients. Between August 2011 and May 2014, we enrolled 82 patients with 90 aneurysms in an open-label uncontrolled clinical trial. All provided prior informed consent for inclusion in this study, and all were treated with eplerenone (25-100 mg/d). The primary end points of our study were the rupture and enlargement of the cerebral aneurysms. Of the 82 patients, 80 (88 unruptured aneurysms) were followed for a mean of 21.3 months (153.4 aneurysm-years); 12 patients (15.0%) permanently discontinued taking the drug. One month after the start of eplerenone administration and throughout the follow-up period, eplerenone kept the blood pressure within the normal range. Most notably, no aneurysms smaller than 9 mm ruptured or enlarged. However, of 2 large thrombosed aneurysms, 1 enlarged and the other ruptured. The overall annual rupture rate was .65%; it was 13.16% for aneurysms larger than 10 mm; the overall annual rate for reaching the primary end points was 1.30%. Our observations suggest that eplerenone may help to prevent the growth and rupture of unruptured cerebral aneurysms smaller than 9 mm. To assess its potential long-term clinical benefits, large clinical trials are needed.

Journal of Stroke & Cerebrovascular Diseases


Flow Alteration Therapy for Ruptured Vertebral Artery Dissecting Aneurysms Involving the Posterior Inferior Cerebellar Artery

Surgery for- and endovascular treatment of vertebral artery (VA) dissecting aneurysms involving the origin of the posterior inferior cerebellar artery (PICA) remain challenging. Their ideal treatment is complete isolation of the aneurysm by surgical or endovascular trapping plus PICA reconstruction. However, postoperative lower cranial nerve palsy and medullary infarction are potential complications. We report four patients with VA dissecting aneurysms involving the PICA origin who were treated by occipital artery (OA)-PICA bypass followed by proximal occlusion of the VA and clip ligation of the PICA origin instead of trapping. There were no procedural or ischemic complications. In all patients, angiography performed 2-3 weeks later showed good patency of the bypass graft and complete obliteration of the aneurysm. During the follow-up period ranging from 1 to 14 years, none experienced bleeding. Although retrograde blood flow to the dissecting aneurysm persisted in the absence of trapping, iatrogenic lower cranial nerve injury could be avoided. The decrease in aneurysmal flow might elicit spontaneous thrombosis and prevent aneurysmal rerupture. Our technique might be less invasive than aneurysmal trapping and help to prevent rebleeding.


Correction to: Treatment with the PPARγ Agonist Pioglitazone in the Early Post-ischemia Phase Inhibits Pro-inflammatory Responses and Promotes Neurogenesis Via the Activation of Innate- and Bone Marrow-Derived Stem Cells in Rats.

In the original publication of the article, the second author (Keiko T. Kitazato) was missing.


Bazedoxifene, a selective estrogen receptor modulator, reduces cerebral aneurysm rupture in Ovariectomized rats.

Estrogen deficiency is thought to be responsible for the higher frequency of aneurysmal subarachnoid hemorrhage in post- than premenopausal women. Estrogen replacement therapy appears to reduce this risk but is associated with significant side effects. We tested our hypothesis that bazedoxifene, a clinically used selective estrogen receptor (ER) modulator with fewer estrogenic side effects, reduces cerebral aneurysm rupture in a new model of ovariectomized rats. Ten-week-old female Sprague-Dawley rats were subjected to ovariectomy, hemodynamic changes, and hypertension to induce aneurysms (ovariectomized aneurysm rats) and treated with vehicle or with 0.3 or 1.0 mg/kg/day bazedoxifene. They were compared with sham-ovariectomized rats subjected to hypertension and hemodynamic changes (HT rats). The vasoprotective effects of bazedoxifene and the mechanisms underlying its efficacy were analyzed. During 12 weeks of observation, the incidence of aneurysm rupture was 52% in ovariectomized rats. With no effect on the blood pressure, treatment with 0.3 or 1.0 mg/kg/day bazedoxifene lowered this rate to 11 and 17%, almost the same as in HT rats (17%). In ovariectomized rats, the mRNA level of ERα, ERβ, and the tissue inhibitor of metalloproteinase-2 was downregulated in the cerebral artery prone to rupture at 5 weeks after aneurysm induction; the mRNA level of interleukin-1β and the matrix metalloproteinase-9 was upregulated. In HT rats, bazedoxifene restored the mRNA level of ERα and ERβ and decreased the level of interleukin-1β and matrix metalloproteinase-9. These findings suggest that bazedoxifene was protective against aneurysmal rupture by alleviating the vascular inflammation and degradation exacerbated by the decrease in ERα and ERβ. Our observation that bazedoxifene decreased the incidence of aneurysmal rupture in ovariectomized rats warrants further studies to validate this response in humans.


Treatment Outcome of Carotid Artery Stenting Underwent within 14 Days of Stroke Onset - Consideration of Safety and Efficacy of Urgent Carotid Artery Stenting for Neurologically Progressing Patients

As the safety and effectiveness of urgent carotid artery stenting (CAS) for neurologically progressing patients remain controversial, we retrospectively analyzed the outcome of urgent CAS based on the patients' pathophysiological condition and neuroimaging findings. We divided 71 patients who underwent CAS within 14 days of stroke onset into two groups. Group 1 (n = 35) was comprised of patients with progressing neurologic signs and a reversible ischemic penumbra on magnetic resonance images (MRI). They were treated by urgent CAS. Group 2 (n = 36) was neurologically stable and underwent prophylactic CAS. In all patients we recorded the National Institutes of Health Stroke Scale (NIHSS) score and the modified Rankin scale (mRS). Urgent CAS resulted in significant improvement in the NIHSS score, when compared before and after CAS in group 1 (5.3 ± 4.3, P < 0.01). The rate of good outcomes (mRS 0-2 at 3 months post-CAS) was 48.6% in group 1, and 75% in group 2. The cumulative incidence of ipsilateral stroke between 31 days and 1 year was 5.9% in group 1, and 0% in group 2. The procedural complication rate was similar in both groups (group 1: 5.7%, n = 2; group 2: 5.6%, n = 2). No patient suffered a symptomatic intracerebral hemorrhage. When the pathophysiological status and neuroimaging findings are used to determine patient eligibility for urgent CAS, this treatment improve neurologic outcome and can be performed as safely as prophylactic CAS in our cohort of patients with acute ischemic stroke.


Intra-arterial high signals on arterial spin labeling perfusion images predict the occluded internal carotid artery segment

Arterial spin labeling (ASL) involves perfusion imaging using the inverted magnetization of arterial water. If the arterial arrival times are longer than the post-labeling delay, labeled spins are visible on ASL images as bright, high intra-arterial signals (IASs); such signals were found within occluded vessels of patients with acute ischemic stroke. The identification of the occluded segment in the internal carotid artery (ICA) is crucial for endovascular treatment. We tested our hypothesis that high IASs on ASL images can predict the occluded segment. Our study included 13 patients with acute ICA occlusion who had undergone angiographic and ASL studies within 48 h of onset. We retrospectively identified the high IAS on ASL images and angiograms and recorded the occluded segment and the number of high IAS-positive slices on ASL images. The ICA segments were classified as cervical (C1), petrous (C2), cavernous (C3), and supraclinoid (C4). Of seven patients with intracranial ICA occlusion, five demonstrated high IASs at C1-C2, suggesting that high IASs could identify stagnant flow proximal to the occluded segment. Among six patients with extracranial ICA occlusion, five presented with high IASs at C3-C4, suggesting that signals could identify the collateral flow via the ophthalmic artery. None had high IASs at C1-C2. The mean number of high IAS-positive slices was significantly higher in patients with intra- than extracranial ICA occlusion. High IASs on ASL images can identify slow stagnant and collateral flow through the ophthalmic artery in patients with acute ICA occlusion and help to predict the occlusion site.


Optimal Timing of Diffusion-Weighted Imaging to Avoid False-Negative Findings in Patients With Transient Ischemic Attack

We aimed to investigate the optimal timing of diffusion-weighted imaging (DWI) in patients with transient ischemic attack (TIA). Seventy-three consecutive patients with TIA underwent DWI on admission (initial DWI) and at 24 hours after admission (second DWI). Patients were divided into 2 groups based on initial DWI findings in relation to the second examination: false negative (group 1) and other (group 2). The probability of initial false-negative findings was determined for each hour from TIA onset to initial DWI. Multivariate analysis was used to evaluate the independent risk factors associated with false-negative findings on initial DWI. Of the 73 patients examined (56 men; mean age, 68 years), 9 (12%) were categorized into group 1. The latency from TIA onset to initial DWI was 1.7±0.6 hours for group 1 (range, 1-2.8 hours) and 3.3±2.6 hours for group 2 (range, 35 minutes to 12 hours). The probability of false-negative findings on initial DWI decreased in a time-dependent manner (25%, 21%, and 7% for 1, 2, and 3 hours, respectively), and no false-negative findings were observed on initial DWI performed at >3 hours from symptom onset. Short latency (2 hours) from TIA onset to initial DWI was an independent risk factor related to false-negative findings (odds ratio, 13.11; 95% confidence interval, 1.07-161.38; P=0.045). If the duration between TIA symptom onset and initial DWI is <2 hours, a repeat examination should be performed to minimize the risk of false-positive findings.


Coexistence of Quasi-moyamoya Disease and POEMS Syndrome in a Patient with Intracranial Hemorrhage: A Case Report and Literature Review

POEMS (polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, and skin changes) syndrome is a rare paraneoplastic syndrome elicited by plasma cell dyscrasia. Its clinical manifestations are multiple and stroke is not a recognized feature. A 44-year-old woman with a 3-month history of bilateral lower extremity sensorimotor disturbance was admitted to our hospital. Examinations revealed polyneuropathy, organomegaly, hypothyroidism, monoclonal gammopathy, pelvic plasmacytoma, and elevated serum vascular endothelial growth factor (VEGF) levels. A diagnosis of POEMS was made. Her condition was improved by radiation therapy of her pelvic plasmacytoma and she continued to be seen on an outpatient basis. Five years after her first admission she was re-admitted with sudden-onset right hemiparesis. A brain computed tomography (CT) scan revealed a left intracranial hemorrhage and magnetic resonance (MR) angiography and cerebral angiography showed occlusion of the proximal portion of the bilateral middle cerebral artery and narrowing of the bilateral internal carotid artery at the terminal portion; moyamoya vessels were seen. This is the first report of a patient whose intracranial hemorrhage was attributable to quasi-moyamoya disease associated with POEMS syndrome. We suggest that the POEMS syndrome be ruled out in the differential diagnosis of patients presenting with atypical stroke, multivessel stenotic lesions (moyamoya vessels), and polyneuropathy.


In-hospital ischemic stroke at Tokushima University Hospital

徳島大学病院脳卒中センターにおける院内発症脳卒中の検討

We assessed the current status of patients with acute in-hospital stroke. 63 patients with acute in-hospital stroke were enrolled. The most prevalent subtype of stroke was embolism(n＝24). The main cause of hospitalization were malignant neoplasms in15. Only 5 patients were treated with rt-PA, 8 patients received endovascular interventions. In-hospital stroke is a sever complication of in-patients and is associated with an unfavorable prognosis, but endovascular interventions offer safe and feasible therapeutic treatment options.


Successful emergency carotid endarterectomy after thrombolysis with intravenous recombinant tissue-type plasminogen activator

Acute internal carotid artery (ICA) occlusion may result in severe disability or death. Revascularization by carotid artery stenting after treatment with intravenous (iv) recombinant tissue-type plasminogen activator (rt-PA) has been documented. However, there are few reports on emergency carotid endarterectomy (CEA) within 24 hours after the iv administration of rt-PA. We treated a 58-year-old man with right ICA occlusion with iv rt-PA. Although partial recanalization of the ICA was obtained, severe stenosis at the origin of the ICA persisted and he developed fluctuating neurological deficits. To prevent progressive stroke he underwent CEA 10.5 hours after rt-PA treatment. Thereafter his blood pressure was strictly controlled under sedation. During and after CEA there were no hemorrhagic complications. Our findings suggest that emergency CEA may be an option to address symptomatic severe residual ICA stenosis even after iv rt-PA therapy delivered in the acute stage. J. Med. Invest. 63: 300-304, August, 2016.

The Journal of Medical Investigation : JMI


Hyperhomocysteinemia induced by excessive methionine intake promotes rupture of cerebral aneurysms in ovariectomized rats

Hyperhomocysteinemia (HHcy) is associated with inflammation and a rise in the expression of matrix metalloproteinase-9 (MMP-9) in the vascular wall. However, the role of HHcy in the growth and rupture of cerebral aneurysms remains unclear. Thirteen-week-old female Sprague-Dawley rats were subject to bilateral ovariectomy and ligation of the right common carotid artery and fed an 8 % high-salt diet to induce cerebral aneurysms. Two weeks later, they underwent ligation of the bilateral posterior renal arteries. They were divided into two groups and methionine (MET) was or was not added to their drinking water. In another set of experiments, the role of folic acid (FA) against cerebral aneurysms was assessed. During a 12-week observation period, subarachnoid hemorrhage due to aneurysm rupture was observed at the anterior communicating artery (AcomA) or the posterior half of the circle of Willis. HHcy induced by excessive MET intake significantly increased the incidence of ruptured aneurysms at 6-8 weeks. At the AcomA of rats treated with MET, we observed the promotion of aneurysmal growth and infiltration by M1 macrophages. Furthermore, the mRNA level of MMP-9, the ratio of MMP-9 to the tissue inhibitor of metalloproteinase-2, and the level of interleukin-6 were higher in these rats. Treatment with FA abolished the effect of MET, suggesting that the inflammatory response and vascular degradation at the AcomA is attributable to HHcy due to excessive MET intake. We first demonstrate that in hypertensive ovariectomized rats, HHcy induced by excessive MET intake may be associated with the propensity of the aneurysm wall to rupture.


Site-specific elevation of interleukin-1β and matrix metalloproteinase-9 in the Willis circle by hemodynamic changes is associated with rupture in a novel rat cerebral aneurysm model

The pathogenesis of subarachnoid hemorrhage remains unclear. No models of cerebral aneurysms elicited solely by surgical procedures and diet have been established. Elsewhere we reported that only few rats in our original rat aneurysm model manifested rupture at the anterior and posterior Willis circle and that many harbored unruptured aneurysms at the anterior cerebral artery-olfactory artery bifurcation. This suggests that rupture was site-specific. To test our hypothesis that a site-specific response to hemodynamic changes is associated with aneurysmal rupture, we modified our original aneurysm model by altering the hemodynamics. During 90-day observation, the incidence of ruptured aneurysms at the anterior and posterior Willis circle was significantly increased and the high incidence of unruptured aneurysms at the anterior cerebral artery-olfactory artery persisted. This phenomenon was associated with an increase in the blood flow volume. Notably, the level of matrix metalloproteinase-9 associated with interleukin-1β was augmented by the increase in the blood flow volume, suggesting that these molecules exacerbated the vulnerability of the aneurysmal wall. The current study first demonstrates that a site-specific increase in interleukin-1β and matrix metalloproteinase-9 elicited by hemodynamic changes is associated with rupture. Our novel rat model of rupture may help to develop pharmaceutical approaches to prevent rupture.

Journal of Cerebral Blood Flow and Metabolism


The susceptibility vessel sign containing two compositions on 3-tesla T2*-weighted image and single corticosubcortical infarct on diffusion-weighted image are associated with cardioembolic stroke

Although accurate diagnosis of the ischemic stroke subtype is one of the most important factors for selection of therapeutic approach, it is sometimes difficult at the time of admission. We previously reported that susceptibility vessel sign (SVS) with two layers (termed two-layered SVS) on 3-tesla-T2*-weighted image (T2*-WI) might be useful to predict cardioembolic stroke in patients with cerebral major vessel occlusion. We studied about biomarkers on magnetic resonance imaging (MRI), including two-layered SVS for diagnosing cardioembolic stroke. We included 132 ischemic stroke patients within 24h from onset who suffered internal carotid artery or middle cerebral artery occlusion due to cardioembolic stroke (group CE) or large artery atherosclerosis (group LAA). We studied about biomarkers on MRI such as two-layered SVS and abnormal finding patterns of diffusion-weighted image (DWI) for diagnosis of cardioembolic stroke in addition to laboratory data, physiological examination, and clinical findings. In this study, 132 patients (72 men and 60 women, age 74.5 ± 12.1 years) were included. Of these, 63 (47.7%) were cardioembolic stroke. In univariate analysis, frequency of comorbid atrial fibrillation, presence of two-layered SVS on T2*-WI and that of single corticosubcortical infarct on DWI, intima-media thickness were significantly higher in group CE. In multivariate analysis, the presence of two-layered SVS and single corticosubcortical infarct were associated with cardioembolic stroke (odds ratio, two-layered SVS, 30.08, p<0.001; single corticosubcortical infarct, 15.78, p<0.001). Biomarkers associated with cardioembolic stroke may be two-layered SVS on T2*-WI and single corticosubcortical infarct on DWI.


Protective role of peroxisome proliferator-activated receptor- in the development of intracranial aneurysm rupture

Inflammation is emerging as a key component of the pathophysiology of intracranial aneurysms. Peroxisome proliferator-activated receptor-γ (PPARγ) is a nuclear hormone receptor of which activation modulates various aspects of inflammation. Using a mouse model of intracranial aneurysm, we examined the potential roles of PPARγ in the development of rupture of intracranial aneurysm. A PPARγ agonist, pioglitazone, significantly reduced the incidence of ruptured aneurysms and the rupture rate without affecting the total incidence aneurysm (unruptured aneurysms and ruptured aneurysms). PPARγ antagonist (GW9662) abolished the protective effect of pioglitazone. The protective effect of pioglitazone was absent in mice lacking macrophage PPARγ. Pioglitazone treatment reduced the mRNA levels of inflammatory cytokines (monocyte chemoattractant factor-1, interleukin-1, and interleukin-6) that are primarily produced by macrophages in the cerebral arteries. Pioglitazone treatment reduced the infiltration of M1 macrophage into the cerebral arteries and the macrophage M1/M2 ratio. Depletion of macrophages significantly reduced the rupture rate. Our data showed that the activation of macrophage PPARγ protects against the development of aneurysmal rupture. PPARγ in inflammatory cells may be a potential therapeutic target for the prevention of aneurysmal rupture.


Improvement of plasma biomarkers after switching stroke patients from other angiotensin II type I receptor blockers to olmesartan

Managing hypertension is crucial for preventing stroke recurrence. Some stroke patients experience resistant hypertension. In our experimental stroke model, olmesartan increased the expression of angiotensin (Ang) II converting enzyme-2. We hypothesized that switching to olmesartan affects biomarkers and the blood pressure (BP) in stroke patients whose BP is insufficiently controlled by standard doses of Ang II type I receptor blockers (ARBs) other than olmesartan. We recruited 25 patients to study our hypothesis. All had a history of stroke or silent cerebral infarction. We switched them to olmesartan (10-40 mg per day) for 12 weeks and determined their plasma level of Ang-(1-7), peroxiredoxin, oxidized low-density lipoprotein (oxLDL)/β-2-glycoprotein I (β2GPI) complex, adiponectin, high mobility group box 1 (HMGB1), and tumor necrosis factor-α (TNFα) and recorded their BP before and after olmesartan treatment. After switching the patients to olmesartan, their plasma level of Ang-(1-7) as a vasoprotective indicator and adiponectin regulating metabolic syndrome was increased, and peroxiredoxin and the oxLDL/β2GPI complex indicating its antioxidative stress and its proatherogenicity were lower than their baseline. This suggests that olmesartan may be more effective than other ARBs to improve these conditions. Neither HMGB1 nor TNFα reflecting an inflammatory response was affected, suggesting that the anti-inflammatory effects of olmesartan are similar to those of other ARBs. The recommended BP (<140/90) was obtained in 10 of the 25 patients after switching to olmesartan. No adverse events occurred. Switching from other ARBs to olmesartan may be a promising therapeutic option in patients with resistant hypertension.

Journal of Stroke & Cerebrovascular Diseases


Angiotensin-(1-7) protects against the development of aneurysmal subarachnoid hemorrhage in mice

Angiotensin-(1-7) (Ang-(1-7)) can regulate vascular inflammation and remodeling, which are processes that have important roles in the pathophysiology of intracranial aneurysms. In this study, we assessed the effects of Ang-(1-7) in the development of intracranial aneurysm rupture using a mouse model of intracranial aneurysms in which aneurysmal rupture (i.e., aneurysmal subarachnoid hemorrhage) occurs spontaneously and causes neurologic symptoms. Treatment with Ang-(1-7) (0.5 mg/kg/day), Mas receptor antagonist (A779 0.5 mg/kg/day or 2.5 mg/kg/day), or angiotensin II type 2 receptor (AT2R) antagonist (PD 123319, 10 mg/kg/day) was started 6 days after aneurysm induction and continued for 2 weeks. Angiotensin-(1-7) significantly reduced the rupture rate of intracranial aneurysms without affecting the overall incidence of aneurysms. The protective effect of Ang-(1-7) was blocked by the AT2R antagonist, but not by the Mas receptor antagonist. In AT2R knockout mice, the protective effect of Ang-(1-7) was absent. While AT2R mRNA was abundantly expressed in the cerebral arteries and aneurysms, Mas receptor mRNA expression was very scarce in these tissues. Angiotensin-(1-7) reduced the expression of tumor necrosis factor-α and interleukin-1β in cerebral arteries. These findings indicate that Ang-(1-7) can protect against the development of aneurysmal rupture in an AT2R-dependent manner.


Prevention of retrograde blood flow into large or giant internal carotid artery aneurysms by endovascular coil embolization with high-flow bypass: surgical technique and long-term results

Recanalization has been reported in large or giant aneurysms of the internal carotid artery (ICA) addressed by high-flow bypass and endovascular treatment. Aneurysmal recanalization may be attributable to retrograde blood flow into the aneurysm through the ICA branches, such as the ophthalmic artery or the meningohypophyseal trunk, or through the surgically created bypass. We modified the endovascular treatment of aneurysms to prevent retrograde flow and evaluated the long-term efficacy of our method. We used a hybrid operative/endovascular technique to treat 5 patients with large or giant aneurysms arising from the C2-C4 segment of the ICA who presented with visual symptoms due to the mass effect of the aneurysm. To prevent retrograde flow into the aneurysm our modified endovascular treatment involves coil embolization of the aneurysmal orifice and the ICA, including the origin of the ophthalmic artery and meningohypophyseal trunk, and placement of a high-flow bypass using a radial artery graft. During the 5- to 12-year follow-up period, 4 aneurysms disappeared, and the other decreased in size. There were no subarachnoid hemorrhages. All bypass grafts remained patent. Visual preservation was achieved in 2 patients; 1 patient manifested visual improvement. Although 2 patients experienced transient neurological deficits we encountered no permanent complications in this series. The final modified Rankin scale of the 5 patients was 0 or 1. Prevention of retrograde flow into the aneurysm by coil embolization with high-flow bypass is a safe and effective method. It prevents the recanalization of large or giant ICA aneurysms.


The two-1 layered susceptibility vessel sign on 3-tesla T2*-weighted imaging is a predictive biomarker of stroke subtype

A susceptibility vessel sign (SVS) on 1.5-tesla (T)-T2*-weighted images may predict cardioembolism. It has also been detected in patients with large artery atherosclerosis. In patients with major vessel occlusion, the SVS was comprised 2 layers on 3T-T2*-weighted images. We assessed the efficacy of 2-layered SVS on 3T-T2*-weighted imaging scans for predicting cardioembolism. Our study included 132 patients who had ischemic stroke within the preceding 24 hours and presented with internal carotid artery or middle cerebral artery occlusion because of cardioembolism or large artery atherosclerosis. We compared 2-layered SVS and SVS on 3T-T2*-weighted imaging scans for their sensitivity, specificity, and diagnostic odds ratio for predicting cardioembolism. We enrolled 132 patients (72 men; mean age, 74.5 years); of these, 63 (47.7%) were presented with cardioembolism. Although the sensitivity of SVS and 2-layered SVS for cardioembolism and large artery atherosclerosis was not statistically different (74.6% and 58.0%, respectively), the sensitivity of 2-layered SVS was significantly higher in patients with cardioembolism (42.9%) than those with large artery atherosclerosis (2.9%; P<0.001). The specificity and diagnostic odds ratio for 2-layered SVS for cardioembolism were 97.1% and 25.1; for SVS they were 42.0% and 2.1, respectively. The specificity of 2-layered SVS for cardioembolism was high. It may be useful for predicting cardioembolism and for the management of patients with acute ischemic stroke.


Roles of estrogen in the formation of intracranial aneurysms in ovariectomized female mice

Epidemiological studies have indicated that postmenopausal women have a higher incidence of intracranial aneurysms than men in the same age group. To investigate whether estrogen or estrogen receptors (ERs) mediate protective effects against the formation of intracranial aneurysms. Intracranial aneurysms were induced in mice by combining a single injection of elastase into the cerebrospinal fluid with deoxycorticosterone acetate salt hypertension. The mice were treated with estrogen (17β-estradiol), an ERα agonist (propyl pyrazole triol), and an ERβ agonist (diarylpropionitrile) with and without a nitric oxide synthase inhibitor. The ovariectomized female mice had a significantly higher incidence of aneurysms than the male mice, which was consistent with findings in previous epidemiological studies. In ovariectomized female mice, an ERβ agonist, but not an ERα agonist or 17β-estradiol, significantly reduced the incidence of aneurysms. The protective effect of the ERβ agonist was absent in the ovariectomized ERβ knockout mice. The protective effect of the ERβ agonist was negated by treatment with a nitric oxide synthase inhibitor. The effects of sex, menopause, and estrogen treatment observed in this animal study were consistent with previous epidemiological findings. Stimulation of estrogen receptor-β was protective against the formation of intracranial aneurysms in ovariectomized female mice.


T2強調画像で脊髄内に高信号を呈する病変 圧迫骨折を伴い，両下肢の筋力低下で発症した80歳女性


Post-ischemic hyperperfusion after clipping of a reptured internal carotid-posterior communicating artery aneurysm under suction decomperession

Interdisciplinary Neurosurgery: Advanced Techniques and Case Management


Estrogen protects against intracranial aneurysm rupture in ovariectomized mice

Clinical observations suggest that postmenopausal women have a higher incidence of aneurysmal rupture than premenopausal women. We hypothesize that a relative deficiency in estrogen may increase the risks of aneurysmal growth and subarachnoid hemorrhage in postmenopausal women. We assessed the effects of estrogen and selective estrogen receptor subtype agonists on the development of aneurysmal rupture in ovariectomized female mice. We used an intracranial aneurysm mouse model that recapitulates the key features of human intracranial aneurysms, including spontaneous rupture. Ten- to 12-week-old ovariectomized female mice received treatment with estrogen, nonselective estrogen receptor antagonist, estrogen receptor-α agonist, or estrogen receptor-β agonist starting 6 days after aneurysm induction so that the treatments affected the development of aneurysmal rupture without affecting aneurysmal formation. Estrogen significantly reduced the incidence of ruptured aneurysms and rupture rates in ovariectomized mice. Nonselective estrogen receptor antagonist abolished the protective effect of estrogen. Although estrogen receptor-α agonist did not affect the incidence of ruptured aneurysms or rupture rates, estrogen receptor-β agonist prevented aneurysmal rupture without affecting the formation of aneurysms. The protective role of estrogen receptor-β agonist was abolished by the inhibition of nitric oxide synthase. We showed that estrogen prevented aneurysmal rupture in ovariectomized female mice. The protective effect of estrogen seemed to occur through the activation of estrogen receptor-β, a predominant subtype of estrogen receptor in human intracranial aneurysms and cerebral arteries.


Intra-arterial signal on arterial spin labeling perfusion MRI to identify the presence of acute middle cerebral artery occlusion

The susceptibility vessel sign on gradient echo-type-T2*-weighted imaging is a well-known marker of arterial occlusion. Stagnant flow in front of the middle cerebral artery (MCA) occlusion sites may contribute to the intra-arterial, high-intensity signal on arterial spin labeling magnetic resonance imaging (MRI), making it another potential marker of MCA occlusion. We compared the intra-arterial, high-intensity signal and susceptibility vessel sign in patients with symptomatic MCA occlusion and patients without major vessel occlusion. We identified transient ischemic attack or ischemic stroke patients with (1) 3-T MRI performed within 24 h after clinical onset including arterial spin labeling, T2*-weighted imaging, and magnetic resonance angiography (MRA) and (2) either having MCA occlusion (n = 34 patients) or without major vessel occlusion (n = 24 patients). The intra-arterial, high-intensity signal was defined as an enlarged circular or linear bright hyperintensity within the artery. The susceptibility vessel sign was defined as an enlarged spot of hypointensity within the MCA, in which the diameter of the hypointense signal within the vessel exceeded the contralateral vessel diameter. The presence or absence of the intra-arterial, high-intensity signal and susceptibility vessel sign were assessed, along with their inter-rater agreement and consistency with the presence of MCA occlusion on MRA. The intra-arterial, high-intensity signal was detectable in 30 patients (52%), and susceptibility vessel sign was observed in 17 patients (29%). The sensitivity of the intra-arterial high-intensity signal was significantly higher than that of the susceptibility vessel sign (88% vs. 50%; p < 0.05). The accuracy of the intra-arterial high-intensity signal was also higher than that of the susceptibility vessel sign (93% vs. 71%; p < 0.05). The intra-arterial high-intensity signal was situated in the proximal regions of the susceptibility vessel sign on T2*WI within the MCA. Neither the intra-arterial high-intensity signal nor the susceptibility vessel sign was observed in patients without major vessel occlusion. Inter-rater agreement was good for intra-arterial high-intensity signal detection (κ = 0.73) and moderate for susceptibility vessel sign detection (κ = 0.47). The presence or absence of the intra-arterial high-intensity signal was highly consistent with that of MCA occlusion on MRA (κ = 0.74). The intra-arterial high-intensity signal on arterial spin labeling appears to be useful to identify the presence of acute MCA occlusion and may be associated with stagnant flow in front of occlusion sites. The intra-arterial high-intensity signal may also be used to identify the occlusion site.


Roles of hypertension in the rupture of intracranial aneurysms

Systemic hypertension has long been considered a risk factor of aneurysmal rupture. However, a causal link between systemic hypertension and the development of aneurysmal rupture has not been established. In this study, using a mouse model of intracranial aneurysm rupture, we examined the roles of systemic hypertension in the development of aneurysmal rupture. Aneurysms were induced by a combination of deoxycorticosterone acetate (DOCA)-salt and a single injection of elastase into the cerebrospinal fluid in mice. Antihypertensive treatment was started 6 days after aneurysm induction. Aneurysmal rupture was detected by neurological symptoms and confirmed by the presence of intracranial aneurysm with subarachnoid hemorrhage. Hydralazine (direct vasodilator) or discontinuation of DOCA-salt treatment was used to assess the roles of systemic hypertension. Captopril (angiotensin-converting enzyme inhibitor) or losartan (angiotensin II type 1 receptor antagonist) was used to assess the roles of the local renin-angiotensin system in the vascular wall. Normalization of blood pressure by hydralazine significantly reduced the incidence of ruptured aneurysms and the rupture rate. There was a dose-dependent relationship between reduction of blood pressure and prevention of aneurysmal rupture. Captopril and losartan were able to reduce rupture rate without affecting systemic hypertension induced by DOCA-salt treatment. Normalization of blood pressure after aneurysm formation prevented aneurysmal rupture in mice. In addition, we found that the inhibition of the local renin-angiotensin system independent from the reduction of blood pressure can prevent aneurysmal rupture.


Treatment Outcomes in Patients Older than 80 Years Presenting with Ruptured Intracranial Aneurysms

80歳以上の破裂脳動脈瘤の治療成績

While the number of elderly patients who presented with aneurysmal subarachnoid hemorrhage (SAH) has been increasing, its optimal management in that population remains controversial. Therefore, we retrospectively reviewed the treatment outcomes in 49 consecutive patients aged between 80 and 94 years who presented with SAH. The neurological World Federation of Neurological Surgeons (WFNS) grade at the time of admission was Grade I in 7, Grade II in 11, Grade III in 8, Grade IV in 13, and Grade V in 10 patients. Of the 49 patients, 28 underwent coil embolization, and 7 (25%) had a favorable outcome (mRS: 0-2) at discharge, while in 21 (75%) the outcome was poor (mRS: 3-6). Six patients underwent clipping; the outcome was favorable in one patient (17%) and poor in 5 (83%). Of 15 patients under conservative therapy none had a favorable outcome. A low WFNS grade (I-II) was significantly associated with a favorable outcome (p<0.05). Although the treatment outcome in elderly patients with SAH was poor, radical treatment of ruptured aneurysms should be considered if their WFNS grade is low.


Nihon Rinsho. Japanese Journal of Clinical Medicine


脳動脈瘤におけるNa+蓄積とRASの影響

脳動脈瘤におけるNa+蓄積とRASの影響


A Case of Cervical Extradural Arteriovenous Fistula presenting with Radiculopathy

Radiculopathy で発症した頚椎硬膜外病変の1例


A clinical study on severe neurogenic stress cardiomyopathy after subarachnoid hemorrhage


Activation of signal transducer and activator of transcription-3 by a peroxisome proliferator-activated receptor gamma agonist contributes to neuroprotection in the peri-infarct region after ischemia in oophorectomized rats

The role of the phosphorylated signal transducer and activator of transcription-3 (p-STAT3) after cerebral ischemia by the peroxisome proliferator-activated receptor (PPAR) agonist pioglitazone (PGZ) remains controversial. Whether the increase in p-STAT3 by estrogen is mediated by the estrogen receptor is also obscure. We examined the role of p-STAT3, PPAR, and estrogen receptor against ischemic brain damage after PGZ treatment. Female Wistar rats subjected or not subjected to bilateral oophorectomy were injected with 1.0 or 2.5 mg/kg PGZ 2 days, 1 day, and 1 hour before 90-minute middle cerebral artery occlusion-reperfusion and compared with vehicle-control rats. The cortical infarct size was larger in ovariectomized than in nonovarietomized rats; it was reduced by PGZ treatment. Inversely with the reduction of the infarct size, PPAR, and p-STAT3 but not estrogen receptor in the peri-infarct area were increased in PGZ-treated compared with vehicle-control rats. The increase in PPAR and p-STAT3 was associated with the transactivation of antiapoptotic and survival genes and the reduction of caspase-3 in this area. Inhibitors of PPAR or STAT3 abolished the PGZ-induced neuroprotection and the increase in p-STAT3. More importantly, p-STAT3 increased by PGZ was bound to PPAR and the complex translocated to the nucleus to dock to the response element through p-STAT3. Our findings suggest that the activation in the peri-infarct region of p-STAT3 and PPAR by PGZ is essential for neuroprotection after ischemia and that PGZ may be of benefit even in postmenopausal stroke patients.


Increase in body Na+-to-water ratio is associated with cerebral aneurysm formation in oophorectomized rats

The incidence of cerebral aneurysms is higher in women than in men, especially postmenopause. Although hypertension is thought to be associated with a high incidence of stroke, not all patients with unruptured cerebral aneurysms are hypertensive. The possibility of water-free Na(+) storage associated with hypertension has been raised. However, whether the increase in the body Na(+)/water ratio that characterizes water-free Na(+) accumulation is associated with the formation of cerebral aneurysms remains obscure. To examine this relationship, Sprague-Dawley female rats subjected to carotid artery ligation were divided into 3 groups: a high-salt diet group (HSD) without and another with bilateral oophorectomy (HSD/OVX) and a third group that underwent additional renal artery ligation (HSD/OVX/RL). Compared with rats receiving a normal diet (shams), water retention was increased in HSD rats but not in HSD/OVX rats. Interestingly, compared with HSD rats, the incidence of cerebral aneurysms and the body Na(+)/water ratio were significantly higher in HSD/OVX and HSD/OVX/RL rats, independent of hypertension. In their aneurysmal wall, ATP12, a subtype of Na(+)/K(+)-ATPase, was downregulated, whereas inflammatory-related molecules were upregulated. Treatment with low-dose olmesartan that did not affect the blood pressure in hypertensive HSD/OVX/RL rats reduced the rate of cerebral aneurysm formation, body Na(+) retention, and the Na(+)/water ratio and upregulated ATP12. These results suggest that the increase in the Na(+)/water ratio and a reduction in ATP12 may be associated with cerebral aneurysm formation. We provide the new insight that the management of water-free Na(+) is important to prevent their development.


Krüppel-like zinc-finger transcription factor 5 (KLF5) is highly expressed in large and giant unruptured cerebral aneurysms.

Krüppel-like zinc-finger transcription factor 5 (KLF5), known as BTEB2 and IKLF, has several biological functions that involve cell proliferation, development, and apoptosis. In human cerebral aneurysms, macrophage infiltration is profoundly associated with growth and rupture, but the role of KLF5 remains unclear. We examined the significance of KLF5 expression in cerebral aneurysms. Unruptured (n=15) and ruptured (n=12) aneurysms obtained at surgery or autopsy were divided into 3 size groups: small (<10 mm); large (10 mm but <25 mm); and giant (25 mm). Control samples comprised 5 cerebral arteries obtained from surgery or autopsy subjects. The expression of KLF5-, -smooth muscle actin-, and KP-1 (macrophages) -positive cells were counted and compared between groups. Media of control arteries was negative for KLF5. In the luminal layers, KLF5 in unruptured small aneurysm was also negative; KLF5 expression was higher in unruptured large/giant aneurysms than other groups (P<0.05). KP-1 expression in unruptured large/giant aneurysms, ruptured small aneurysms, and ruptured large/giant aneurysms was higher than in unruptured small aneurysms (P<0.05). In the unruptured large/giant aneurysms, KP-1-positive cells were lower than KLF5-positive cells. On the other hand, irrespective of size, KLF5 positivity tended to be lower than KP-1 in the luminal and abluminal layers of all ruptured aneurysms. This represents the first documentation that KLF5 is highly expressed in large and giant unruptured aneurysms and that in ruptured aneurysmal wall KLF5 expression was scarce. These findings suggest that the KLF5 expression and macrophage infiltration play essential roles on aneurysmal growth or rupture.


Statins Promote the Growth of Experimentally Induced Cerebral Aneurysms in Estrogen-Deficient Rats

The pathogenesis of cerebral aneurysms is linked to inflammation, degradation of the extracellular matrix, and vascular wall apoptosis. Statins exert pleiotropic effects on the vasculature, independent of their cholesterol-lowering properties. To explore the detailed pathogenesis of cerebral aneurysms, we examined their progression in a rat model and studied whether statins prevent their initiation and growth. Cerebral aneurysms were induced in female rats subjected to hypertension, increased hemodynamic stress, and estrogen deficiency. The development of aneurysm was assessed morphologically on corrosion casts. The effects of pravastatin (5, 25, or 50 mg/kg per day) and of simvastatin (5 mg/kg per day) on their aneurysms were studied. Human brain endothelial cells were also used to determine the effects of pravastatin. Pravastatin (5 mg/kg per day) reduced endothelial damage and inhibited aneurysm formation; there was an association with increased endothelial nitric oxide synthase (eNOS) levels and a decrease in human brain endothelial cell adhesion molecules. Unexpectedly, 25 mg/kg per day and 50 mg/kg per day pravastatin and 5 mg/kg per day simvastatin promoted aneurysmal growth, and high-dose pravastatin induced aneurysmal rupture. The deleterious effects exerted by these statins were associated with an increase in apoptotic caspase-3 levels and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL)-positive cells, suggesting that statins exert bidirectional effects. Our results provide the first evidence that cerebral aneurysm growth is partly associated with apoptosis and issue a warning that statins exert bidirectional effects on cerebral aneurysms. Additional intensive research is necessary to understand better their mechanisms and to identify patients in whom the administration of statins may elicit deleterious effects.


Activation of estrogen receptor- and of angiotensin-converting enzyme 2 suppresses ischemic brain damage in oophorectomized rats.

Like the angiotensin II type 1 receptor blocker, endogenous estrogen (17-estradiol) is neuroprotective against cerebral ischemia; its effects are thought to be mediated by estrogen receptors (ERs). To verify the role of ERs and the brain renin-angiotensin system in estrogen-deficient rats with ischemia induced by middle cerebral artery occlusion, we compared rats subjected to oophorectomy (OVX(+)) with sham-oophorectomized rats (OVX(-)) and OVX(+) rats treated with 0.3 or 3.0 mg/kg of olmesartan for 2 weeks before middle cerebral artery occlusion. Independent of the blood pressure, the cortical infarct volume was larger in OVX(+) than in OVX(-) rats. It was smaller in olmesartan-pretreated OVX(+) rats. The expression of ER in the peri-infarct region was correlated with the reduction of cortical infarct but not that of ER or G protein-coupled estrogen receptor. Olmesartan prevented ER downregulation in the cortical peri-infarct area, without affecting ER or G protein-coupled estrogen receptor. Olmesartan also increased mRNA expression of angiotensin-converting enzyme 2, Bcl-2, and Bcl-xL and reduced angiotensin II and cleaved caspase 3. These effects were augmented by olmesartan and abolished by the ER inhibitor. In OVX(+) rats treated with the ER agonist alone, the infarct size was decreased, and the neuroprotective genes were upregulated. These findings suggest that the transactivation of neuroprotective genes and the reduction in brain angiotensin II are ER dependent and that this may augment neuroprotection together with an angiotensin II type 1 receptor blockade by olmesartan. We present the new insight that the activation of ER independent of estrogen contributes at least partly to limiting cerebral ischemic damage.


Reduction of endothelial tight junction proteins is related to cerebral aneurysm formation in rats.

OBJECTIVE: The formation of cerebral aneurysms is associated with endothelial damage and macrophage migration. Hypothesizing that the opening of tight junctions due to the disappearance of the tight junction proteins occludin and zona occludens-1 (ZO-1) in damaged endothelia allows macrophage migration, leading to cerebral aneurysm formation, we investigated the role of tight junction proteins. METHODS: The vascular wall of female rats subjected to hypertension, oophorectomy (OVX), and hemodynamic stress to induce cerebral aneurysms was evaluated morphologically, immunohistochemically, and by quantitative RT-PCR. We also assessed the regulation of tight junction proteins in human brain endothelial cells (HBECs). RESULTS: In the very early stage before aneurysm formation, the expression of occludin and ZO-1 was reduced in injured endothelial cell junctions exhibiting gaps. In the course of aneurysmal progression their reduction progressed and was correlated with macrophage migration. In hypertension along with OVX rats we observed an increase in angiotensin II and the degradation molecules matrix metalloproteinase-9 (MMP-9), nicotinamide-adenine dinucleotide phosphate oxidases and monocyte chemoattractant protein-1. The mineralocorticoid receptor blocker eplerenone increased occludin and ZO-1 expression; this was associated with a reduction in angiotensin II and the degradation molecules and resulted in the inhibition of macrophage exudation and aneurysm formation. In HBECs, occludin and ZO-1 downregulation by angiotensin II and estrogen deficiency was reversed by eplerenone, the MMP inhibitor SB3CT, and apocynin. Our results suggest that macrophage migration is associated with the reduction in tight junction proteins induced by the degradation molecules. CONCLUSION: In rats, the destruction of tight junctions may facilitate macrophage migration and cerebral-aneurysm formation.


Ibudilast inhibits cerebral aneurysms by down-regulating inflammation-related molecules in the vascular wall of rats.

OBJECTIVE: Phosphodiesterase-4 (PDE-4) is a cyclic adenosine monophosphate-specific enzyme involved in various inflammatory diseases. We studied its role in and the effect of ibudilast, which predominantly blocks PDE-4, on rat cerebral aneurysms. METHODS: Cerebral aneurysms were induced at the anterior cerebral artery-olfactory artery bifurcation of female rats subjected to hypertension, increased hemodynamic stress, and estrogen deficiency. The effect of ibudilast (30 or 60 mg/kg/d for 3 months) on their cerebral aneurysms was studied by morphological and immunohistochemical assessment and quantitative real-time polymerase chain reaction assay. In our in vitro study, we grew endothelial cells stimulated by angiotensin II under estrogen-free conditions and examined the effect of ibudilast on PDE-4 activation and the cyclic adenosine monophosphate level. RESULTS: Morphological evaluation using vascular corrosion casts showed ibudilast significantly suppressed cerebral aneurysms in a dose-dependent manner. In rats with induced cerebral aneurysms, the gene and protein expression of PDE-4 was high, and endothelial leukocyte adhesion molecules (P-selectin, intracellular adhesion molecule 1, and vascular adhesion molecule 1), matrix metalloproteinase-9, and tumor necrosis alpha were expressed. Macrophage migration was also increased. Treatment with ibudilast down-regulated these molecules, suppressed macrophage migration into the aneurysm wall, and inhibited PDE-4 activation and the elevation of cyclic adenosine monophosphate in endothelial cells. CONCLUSION: These results suggest that blocking of PDE4 is associated with the reduction of inflammation-related molecules and macrophage migration, thereby reducing the progression of cerebral aneurysms. It may represent a new conservative therapy to treat patients with cerebral aneurysms.


Reversibility of ischemic findings on 3-T T2*-weighted imaging after emergency superficial temporal artery-middle cerebral artery anastomosis in patients with progressive ischemic stroke.

Vascular ischemic signs, i.e. multiple hypointense vessels in the ischemic territory, were identified by gradient echo-type 3-T T(2)*-weighted magnetic resonance (MR) imaging in 3 patients with acute ischemia due to major vessel occlusion. Emergency superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis was performed in 2 patients with progressive stroke caused by bleeding-type moyamoya disease or severe MCA stenosis. Both patients were initially treated conservatively, but their neurological signs deteriorated. 3-T T(2)*-weighted MR imaging detected funicular low signals in both patients indicating enhancement of cortical vessels or medullary veins. The area of the vascular ischemic signs was almost the same or smaller than the hypoperfusion area on perfusion-weighted MR imaging or single-photon emission computed tomography. Postoperatively, the vascular ischemic signs disappeared in both patients, suggesting a relationship with severe ischemia due to high-risk misery perfusion. Their postoperative course was uneventful, and MR imaging revealed no new cerebral ischemic lesions or cerebral hyperperfusion. The patient without surgery developed cerebral infarction in the area of the vascular ischemic signs. Vascular ischemic signs detected by 3-T T(2)*-weighted MR imaging may represent a new predictor of high-risk misery perfusion, and may disappear after STA-MCA anastomosis performed in the subacute stage.


Role of mineralocorticoid receptor on experimental cerebral aneurysms in rats.

Activation of the renin-angiotensin (Ang)-aldosterone system is involved in the pathology of vascular diseases. Although the blockade of the mineralocorticoid receptor protects against vascular diseases, its role in cerebral aneurysms remains to be elucidated. We treated female rats subjected to renal hypertension, increased hemodynamic stress, and estrogen deficiency for 3 months with the mineralocorticoid receptor blocker eplerenone (30 or 100 mg/kg per day) or vehicle (vehicle control). Eplerenone reduced the incidence of cerebral aneurysms and saline intake without lowering of the blood pressure. In the aneurysmal wall, the production of Ang II and nitrotyrosine was increased. The mRNA levels of Ang-converting enzyme 1 and NADPH oxidase subunits NOX4, Rac1, monocyte chemoattractant protein 1, and matrix metalloproteinase 9 were increased. Eplerenone brought about a reduction in these molecules, suggesting that mineralocorticoid receptor blockade suppresses cerebral aneurysm formation by inhibiting oxidative stress, inflammatory factors, local renin-Ang system activation, and saline intake. Other female rats implanted with pellets of the mineralocorticoid receptor agonist deoxycorticosterone acetate manifested a high incidence of cerebral aneurysm formation and the upregulation of molecules related to oxidative stress, inflammatory factors, and the local renin-Ang system; their saline intake was increased. We demonstrate that mineralocorticoid receptor activation at least partly contributes to the pathogenesis of cerebral aneurysms.


Endothelial damage due to impaired nitric oxide bioavailability triggers cerebral aneurysm formation in female rats

Epidemiological data indicate a high incidence of cerebral aneurysms in postmenopausal women. To elucidate the pathogenesis of cerebral aneurysms, we focused on the contribution of endothelial damage in rats. We induced estradiol deficiency by oophorectomy (OVX), hypertension, or both, and hemodynamic stress in 7-week-old female Sprague-Dawley rats. They were then given hormone-replacement therapy with 17beta-estradiol or an angiotensin II type 1 receptor blocker (ARB). The effects of estradiol, angiotensin II type 1 receptor blocker, or both on cultured endothelial cells were also examined. The number of anomalously shaped endothelial cells was higher in OVX than hypertensive rats (P < 0.05). Rats subjected to hypertension and OVX exhibited a marked increase in the incidence of saccular cerebral aneurysms. Estradiol or angiotensin II type 1 receptor blocker treatment reduced this incidence (P < 0.05). The endothelial nitric oxide synthase (eNOS) mRNA level in the intracranial artery of OVX and hypertensive and OVX rats was low (P < 0.05). Immunohistochemically, the expression of eNOS and estrogen receptor alpha (ERalpha) in the vascular wall of hypertensive and OVX rats was decreased; angiotensin II and the nicotinamide adenine dinucleotide phosphate oxidase subunits nicotinamide adenine dinucleotide phosphate oxidase 4 and p22phox were strongly expressed in cerebral aneurysms. In the absence of estradiol, eNOS was downregulated and nicotinamide adenine dinucleotide phosphate oxidase expression was increased in endothelial cells; angiotensin II augmented these phenomena. The regulation of eNOS was mediated by ERalpha. These results suggest that estrogen deficiency induces endothelial dysfunction and reactive oxygen species generation, triggering endothelial damage that leads to cerebral aneurysms and that hypertension is an additional risk factor. A therapy targeted at the endothelium and management of hypertension may help to prevent cerebral aneurysms.


Edaravone, a free radical scavenger, inhibits MMP-9-related brain hemorrhage in rats treated with tissue plasmininogen activator

Intracerebral hemorrhage, induced by recombinant tissue plasminogen activator (rtPA) in ischemic stroke, is attributable to the increased activity of matrix metalloproteinase-9 (MMP-9). Patients with acute infarct benefit from the neuroprotective drug edaravone, a free radical scavenger. We examined the mechanisms by which edaravone may help to suppress rtPA-induced brain hemorrhage. Male Wistar rats weighing 250 to 280 g were subjected to 3-hour transient middle cerebral artery occlusion (MCAO) and divided randomly into 3 groups. Immediately after reperfusion, 1 group was intravenously injected with 10 mg/kg rtPA, another with rtPA plus 3 mg/kg edaravone, and the 3rd group received no treatment. We assessed the hemorrhage volume and the activity of MMP-9 in the brain 24 hours postischemia. We also studied the activity of MMP-9, its mRNA expression, and nuclear factor-kappa B (NF-kappaB) activity in rtPA-stimulated human microvascular endothelial cells (HBECs). The degree of hemorrhage and the level of endothelial cell-derived MMP-9 were elevated in rats treated with rtPA alone and attenuated in rats treated with rtPA plus edaravone. In rtPA-stimulated HBECs, edaravone suppressed the activity and mRNA expression of MMP-9 in a dose-dependent manner. Edaravone also inhibited NF-kappaB activation. We demonstrate that edaravone inhibits rtPA-induced cerebral hemorrhage in the ischemic brain of rats via the inhibition of MMP-9 expression in vivo, which is substantiated by inhibition of MMP-9 expression and NF-kappaB activation in HBECs. Edaravone may render thrombolytic therapy safer for the administration of rtPA in patients with ischemic stroke.


Protective mechanisms of the angiotensin II type 1 receptor blocker candesartan against cerebral ischemia: in-vivo and in-vitro studies

Angiotensin II type 1 (AT1) receptor blockers decrease ischemia by mechanisms dependent on and independent of arterial blood pressure in hypertensive rats and AT1-R knockout mice, respectively. However, the detailed mechanisms underlying the effects of AT1 receptor blockers remain unclear. To elucidate the systemic and focal effects of AT1 receptor blockers against cerebral ischemia in in-vivo and in-vitro studies. Normotensive Wistar rats were treated for 2 weeks with 0.5 or 1 mg/kg candesartan cilexetil and then subjected to 2-h middle cerebral artery occlusion-reperfusion. Human umbilical endothelial cells were stimulated with the active form of candesartan and angiotensin II in the absence and presence of an angiotensin II type 2 (AT2) receptor antagonist. In candesartan-pretreated hypotensive and nonhypotensive rats, blood pressure was moderately increased during middle cerebral artery occlusion and fell gradually to the baseline after the reperfusion; it remained elevated in the control even after the reperfusion occlusion. Candesartan treatment resulted in a decrease in the cortical infarct volume and oxidative damage, the hypoxic status was improved, and the expression of repair-associated and growth-associated proteins in the cortical penumbra was augmented. Candesartan also increased the eNOS mRNA level and the lumen size of the middle cerebral artery. In human umbilical endothelial cells, candesartan increased the eNOS protein level AT2-R dependently, inhibited the expression of nicotinamide adenine dinucleotide phosphate oxidase subunits and angiotensin II-induced intracellular reactive oxygen species and nitric oxide, and promoted the extracellular release of nitric oxide, suggesting that it augmented the bioavailability of nitric oxide. Among the mechanisms candesartan exerts in its protection against cerebral ischemia, restoration of endothelial function may represent an attractive therapeutic goal to address cerebral ischemia.


Usefulness of a novel higher brain dysfunction screening test for evaluating higher brain function in healthy persons.

To accurately and rapidly screen for higher brain dysfunction, we developed a screening test named the "higher brain dysfunction screening test" (HIBRID-ST). Previous studies have reported a decrease in higher brain function with age. However, whether HIBRID-ST can detect a decrease in higher brain function in healthy persons remains unclear. We aimed to assess the usefulness of HIBRID-ST for evaluating higher brain function in healthy persons. We recruited 60 persons without physiological abnormalities and divided them into six equal groups based on their age (20s-70s). HIBRID-ST addresses orientation, short-term memory, word recall, situational awareness, visual short-term memory, and graphic replication and includes the Trail Making and Kana-hiroi tests. There was a significant negative correlation between the participants' age and their total HIBRID-ST score (ϱ = -0.68, p < 0.01). The total HIBRID-ST score of participants in their 70s was significantly lower than that of participants in their 20s-60s; the total HIBRID-ST score of participants in their 60s was significantly lower than that of participants in their 20s-50s. Our findings show that HIBRID-ST accurately detects an age-related decline in higher brain function. Further studies are needed to examine the usefulness of HIBRID-ST in patients with higher brain dysfunction. J. Med. Invest. 64: 280-285, August, 2017.

The Journal of Medical Investigation : JMI


T2強調画像で脊髄内に高信号を呈する病変

T2強調画像で脊髄内に高信号を呈する病変


T2*強調画像における脳静脈洞，皮質静脈の低信号病変

T2*強調画像における脳静脈洞，皮質静脈の低信号病変