Association between Living Conditions and the Risk Factors, Etiology, and Outcome of Ischemic Stroke in Young Adults

Objective In recent decades, living conditions have changed drastically. However, there are few data regarding the interaction between living conditions and the risk of ischemic stroke (IS) in young adults. The present study explored the association between living conditions or marital status and the risk factors, etiology, and outcome of IS in young adults. Methods We prospectively enrolled patients with incident IS who were 20-49 years old from 37 clinical stroke centers. We collected the demographic data, living conditions, marital status, vascular risk factors, disease etiology, treatment, and outcomes at discharge. A comparison group was established using the official statistics of Japan. We categorized patients into the two groups based on living conditions: solitary group and cohabiting group. Clinical characteristics were then compared between living conditions. Results In total, 303 patients were enrolled (224 men; median age at the onset: 44 years old). Significant factors associated with the incidence of IS were as follows: solitary status, body mass index >30 kg/m2, current smoking, heavy alcohol consumption, hypertension, diabetes mellitus, and dyslipidemia. Furthermore, in the solitary group, the proportions of men, unmarried individuals, and current smokers were significantly higher than in the cohabiting group. In addition, poor outcomes (modified Rankin Scale ≥4) of IS were more common in the solitary group than in the cohabiting group. Conclusion Our study showed that not only conventional vascular risk factors but also living conditions, especially living alone while unmarried, were independent risk factors for IS in young adults.

iPSC-derived mesenchymal stem cells attenuate cerebral ischemia-reperfusion injury by inhibiting inflammatory signaling and oxidative stress

Induced pluripotent stem cell-derived mesenchymal stem cells (iMSCs) hold great promise as a cell source for transplantation into injured tissues to alleviate inflammation. However, the therapeutic efficacy of iMSC transplantation for ischemic stroke remains unknown. In this study, we evaluated the therapeutic effects of iMSC transplantation on brain injury after ischemia-reperfusion using a rat transient middle cerebral artery occlusion model and compared its therapeutic efficacy with that of bone marrow mesenchymal stem cells (BMMSCs). We showed that iMSCs and BMMSCs reduced infarct volumes after reperfusion and significantly improved motor function on days 3, 7, 14, 28, and 56 and cognitive function on days 28 and 56 after reperfusion compared with the vehicle group. Furthermore, immunological analyses revealed that transplantation of iMSCs and BMMSCs inhibited microglial activation and expression of proinflammatory cytokines and suppressed oxidative stress and neuronal cell death in the cerebral cortex at the ischemic border zone. No difference in therapeutic effect was observed between the iMSC and BMMSC groups. Taken together, our results demonstrate that iMSC therapy can be a practical alternative as a cell source for attenuation of brain injury and improvement of neurological function because of the unlimited supply of uniform therapeutic cells.

Stroke in Patients With Common Noncancerous Gynecologic Diseases: A Multicenter Study in Japan

Background and Objectives

Gynecologic diseases such as uterine fibroids, endometriosis, and adenomyosis are common in women of reproductive age. Case reports and small case series have reported ischemic stroke in women with such common noncancerous gynecologic diseases, and their cause of stroke is frequently attributed to cryptogenic stroke or unconventional mechanisms related to hypercoagulability. However, stroke etiology and prognosis are not well known. We assessed the prevalence of and stroke mechanisms related to common noncancerous gynecologic diseases using hospital-based clinical data.

Methods

We retrospectively identified consecutive female patients with common noncancerous gynecologic diseases (uterine fibroids, endometriosis, and adenomyosis) diagnosed with ischemic stroke/transient ischemic attack (TIA) between the ages of 20 and 59 years admitted to 10 stroke centers in Japan by reviewing prospectively collected data between 2017 and 2019. The clinical, laboratory, and neuroimaging features were evaluated and compared between patients with conventional stroke mechanisms (CSMs) (large artery atherosclerosis, small vessel occlusion, cardioembolism, and other determined etiology) and non-CSMs (cryptogenic stroke and causes related to hypercoagulability such as nonbacterial thrombotic endocarditis and paradoxical embolism) according to the Trial of Org 10172 in Acute Stroke Treatment criteria.

Results

Of the 470 female patients with ischemic stroke/TIA, 39 (8%) (37 ischemic stroke and 2 TIA) had common noncancerous gynecologic diseases. The most common gynecologic diseases were uterine fibroids in 24 (62%) patients, followed by endometriosis in 9 (23%) and adenomyosis in 6 (15%). Twenty patients (51%) were assigned to the non-CSMs group, and 19 patients (49%) were assigned to the CSMs group. Adenomyosis and endometriosis were more frequent in the non-CSMs group than in the CSMs group. CA125 and D-dimer levels were higher in the non-CSMs group than in the CSMs group. Multiple vascular territory infarcts were frequent in patients with adenomyosis (60%) and endometriosis (43%) in the non-CSMs group. No stroke recurrence or death was observed within 3 months after discharge in both the CSMs and non-CSMs groups. Outcomes at 3 months after discharge were similar in both groups.

Discussion

In patients with common noncancerous gynecologic diseases, hypercoagulopathy may play a role in the pathogenesis of ischemic stroke/TIA without CSMs.

Immunomodulatory amnion-derived mesenchymal stromal cells preserve muscle function in a mouse model of Duchenne muscular dystrophy

BACKGROUND

Duchenne muscular dystrophy (DMD) is an incurable genetic disease characterized by degeneration and necrosis of myofibers, chronic inflammation, and progressive muscle weakness resulting in premature mortality. Immunosuppressive multipotent mesenchymal stromal cell (MSC) therapy could be an option for DMD patients. We focused on amnion-derived mesenchymal stromal cells (AMSCs), a clinically viable cell source owing to their unique characteristics, such as non-invasive isolation, mitotic stability, ethical acceptability, and minimal risk of immune reaction and cancer. We aimed to identify novel immunomodulatory effects of AMSCs on macrophage polarization and their transplantation strategies for the functional recovery of skeletal and cardiac muscles.

METHODS

We used flow cytometry to analyze the expression of anti-inflammatory M2 macrophage markers on peripheral blood mononuclear cells (PBMCs) co-cultured with human AMSCs (hAMSCs). hAMSCs were intravenously injected into DMD model mice (mdx mice) to assess the safety and efficacy of therapeutic interventions. hAMSC-treated and untreated mdx mice were monitored using blood tests, histological examinations, spontaneous wheel-running activities, grip strength, and echocardiography.

RESULTS

hAMSCs induced M2 macrophage polarization in PBMCs via prostaglandin E₂ production. After repeated systemic hAMSC injections, mdx mice exhibited a transient downregulation of serum creatin kinase. Limited mononuclear cell infiltration and a decreased number of centrally nucleated fibers were indicative of regenerated myofibers following degeneration, suggesting an improved histological appearance of the skeletal muscle of hAMSC-treated mdx mice. Upregulated M2 macrophages and altered cytokine/chemokine expressions were observed in the muscles of hAMSC-treated mdx mice. During long-term experiments, a significant decrease in the grip strength in control mdx mice significantly improved in the hAMSC-treated mdx mice. hAMSC-treated mdx mice maintained running activity and enhanced daily running distance. Notably, the treated mice could run longer distances per minute, indicating high running endurance. Left ventricular function in DMD mice improved in hAMSC-treated mdx mice.

CONCLUSIONS

Early systemic hAMSC administration in mdx mice ameliorated progressive phenotypes, including pathological inflammation and motor dysfunction, resulting in the long-term improvement of skeletal and cardiac muscle function. The therapeutic effects might be associated with the immunosuppressive properties of hAMSCs via M2 macrophage polarization. This treatment strategy could provide therapeutic benefits to DMD patients.

Transgenic type2 diabetes mouse models for in vivo redox measurement of hepatic mitochondrial oxidative stress

BACKGROUND

Oxidative stress is involved in the progression of diabetes and its associated complications. However, it is unclear whether increased oxidative stress plays a primary role in the onset of diabetes or is a secondary indicator caused by tissue damage. Previous methods of analyzing oxidative stress have involved measuring the changes in oxidative stress biomarkers. Our aim is to identify a novel approach to clarify whether oxidative stress plays a primary role in the onset of diabetes.

METHODS

We constructed transgenic type 2 diabetes mouse models expressing redox-sensitive green fluorescent proteins (roGFPs) that distinguished between mitochondria and whole cells. Pancreas, liver, skeletal muscle, and kidney redox states were measured in vivo.

RESULTS

Hepatic mitochondrial oxidation increased when the mice were 4 weeks old and continued to increase in an age-dependent manner. The increase in hepatic mitochondrial oxidation occurred simultaneously with weight gain and increased blood insulin levels before the blood glucose levels increased. Administering the oxidative stress inducer acetaminophen increased the vulnerability of the liver mitochondria to oxidative stress.

CONCLUSIONS

This study demonstrates that oxidative stress in liver mitochondria in mice begins at the onset of diabetes rather than after the disease has progressed.

GENERAL SIGNIFICANCE

RoGFP-expressing transgenic type 2 diabetes mouse models are effective and convenient tools for measuring hepatic mitochondrial redox statuses in vivo. These models may be used to assess mitochondria-targeting antioxidants and establish the role of oxidative stress in type 2 diabetes.

FLAMES with Elevated Myelin Basic Protein Followed by Myelitis

The pathophysiology of unilateral cortical fluid-attenuated inversion recovery (FLAIR)-hyperintense lesions in anti-myelin oligodendrocyte glycoprotein (MOG)-associated encephalitis with seizures (FLAMES) is unclear. A 26-year-old man was referred because of a seizure. FLAIR showed an increased signal intensity and swelling of the right frontal cortex. His symptoms and imaging abnormalities were improved after intravenous methylprednisolone therapy. MOG antibody was detected both in serum and cerebrospinal fluid (CSF). Therefore, the patient was diagnosed with FLAMES. Myelin basic protein (MBP) was elevated in CSF. The high MBP value in the CSF in the present case suggested that demyelination as well as inflammation can occur in some FLAMES patients.

Randomised placebo-controlled multicentre trial to evaluate the efficacy and safety of JTR-161, allogeneic human dental pulp stem cells, in patients with Acute Ischaemic stRoke (J-REPAIR)

INTRODUCTION

JTR-161 is a novel allogeneic human cell product consisting of dental pulp stem cells isolated from the extracted teeth of healthy adults. It is currently under development as a cell-based therapy for ischaemic stroke. The aim of this study is to evaluate the safety and efficacy of JTR-161 in patients with acute ischaemic stroke when given as a single intravenous administration within 48 hours of symptom onset.

METHODS AND ANALYSIS

This is a first-in-human, randomised, double-blind, placebo-controlled, multicentre, phase 1/2 clinical trial to be conducted in Japan (from January 2019 to July 2021). Patients with a clinical diagnosis of anterior circulation ischaemic stroke with a National Institutes of Health Stroke Scale (NIHSS）score of 5-20 at baseline were enrolled. Patients previously treated with recombinant tissue-type plasminogen activator and/or endovascular thrombectomy were allowed to be enrolled. The study consists of three cohorts: cohorts 1 and 2 (each eight patients) and cohort 3 (60 patients). Subjects were randomly assigned to receive either JTR-161 or placebo in a 3:1 ratio in cohorts 1 and 2, and in a 1:1 ratio in cohort 3. The number of cells administered was increased sequentially from 1×10⁸ (cohort 1) to 3 x 10⁸ (cohort 2). In cohort 3, the higher tolerated dose among the two cohorts was administered. The primary endpoint is the proportion of patients who achieve an excellent outcome as defined by all of the following criteria at day 91 in cohort 3: modified Rankin Scale ≤1, NIHSS ≤1 and Barthel Index ≥95.

ETHICS AND DISSEMINATION

The protocol and informed consent form were approved by the institutional review board at each participating study site. A manuscript with the results of the primary study will be published in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

NCT04608838; JapicCTI-194570 and Clinical Trials. gov.

Dental-Pulp Stem Cells as a Therapeutic Strategy for Ischemic Stroke

Regenerative medicine aims to restore human functions by regenerating organs and tissues using stem cells or living tissues for the treatment of organ and tissue defects or dysfunction. Clinical trials investigating the treatment of cerebral infarction using mesenchymal stem cells, a type of somatic stem cell therapy, are underway. The development and production of regenerative medicines using somatic stem cells is expected to contribute to the treatment of cerebral infarction, a central nervous system disease for which there is no effective treatment. Numerous experimental studies have shown that cellular therapy, including the use of human dental pulp stem cells, is an attractive strategy for patients with ischemic brain injury. This review describes the basic research, therapeutic mechanism, clinical trials, and future prospects for dental pulp stem cell therapy, which is being investigated in Japan in first-in-human clinical trials for the treatment of patients with acute cerebral ischemia.

The Effect of Aging and Small-Vessel Disease Burden on Hematoma Location in Patients with Acute Intracerebral Hemorrhage

INTRODUCTION

Intracerebral hemorrhage (ICH) is a devastating hemorrhagic event and is associated with high mortality or severe neurological sequelae. Age-associated differences in hematoma location for nonlobar ICH are not well known. The aims of the present study were to elucidate the relationship between age and hematoma location and to assess the differences in small-vessel disease (SVD) burden as a potential surrogate marker for longstanding hypertension among various hematoma locations.

METHODS

From September 2014 through July 2019, consecutive patients with acute, spontaneous ICH were retrospectively enrolled from a prospective registry. Magnetic resonance imaging was performed during admission, and the total SVD burden score (including microbleeds, lacunes, enlarged perivascular spaces, and white matter hyperintensities) was calculated. The relationships of hematoma location with aging and SVD burden were assessed by using multivariate logistic regression analyses.

RESULTS

A total of 444 patients (156 women [35%]; median age 69 [interquartile range 59-79] years; National Institutes of Health Stroke Scale score 9 [17][3-17]) were enrolled in the present study. Multivariate logistic regression analyses showed that advanced age was independently associated with thalamic (odds ratio [OR]: 1.48, 95% confidence interval [CI]: 1.19-1.84, p < 0.001 for 10-year increment) and lobar hemorrhage (OR: 1.58, 95% CI: 1.19-2.09, p = 0.002) and was independently and negatively related to putaminal hemorrhage (OR: 0.55, 95% CI: 0.44-0.68, p < 0.001). The total SVD burden score was independently and positively associated with thalamic hemorrhage (OR: 1.27, 95% CI: 1.01-1.59, p = 0.045) and negatively with lobar hemorrhage (OR: 0.74, 95% CI: 0.55-0.99, p = 0.042), even after adjusting by age, but not with putaminal hemorrhage (OR: 0.91, 95% CI: 0.73-1.14, p = 0.395).

CONCLUSION

Putaminal, thalamic, and lobar hemorrhages are prone to occur in specific ages and SVD states: putaminal in young patients, thalamic in old and high SVD burden patients, and lobar hemorrhages in old and low SVD burden patients. Susceptibility to bleeding with aging or severe SVD accumulation seems to differ considerably among brain locations.

Recent Advances in Cell-Based Therapies for Ischemic Stroke

Stroke is the most prevalent cardiovascular disease worldwide, and is still one of the leading causes of death and disability. Stem cell-based therapy is actively being investigated as a new potential treatment for certain neurological disorders, including stroke. Various types of cells, including bone marrow mononuclear cells, bone marrow mesenchymal stem cells, dental pulp stem cells, neural stem cells, inducible pluripotent stem cells, and genetically modified stem cells have been found to improve neurological outcomes in animal models of stroke, and there are some ongoing clinical trials assessing their efficacy in humans. In this review, we aim to summarize the recent advances in cell-based therapies to treat stroke.

Early Cognitive Assessment Following Acute Stroke: Feasibility and Comparison between Mini-Mental State Examination and Montreal Cognitive Assessment

OBJECTIVES

Cognitive assessment is not performed routinely in the acute stroke setting. We investigated factors associated with cognitive impairment and the differences between the Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA) scores in patients with acute stroke.

METHODS

In this prospective study, 881 consecutive patients (median age, 73 years) with acute stroke were enrolled. Clinical characteristics, such as education, vascular risk factors, premorbid cognitive status using the Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE), and stroke severity, were assessed. Cognitive performance was measured using MMSE and MoCA within 5 days of stroke onset.

RESULTS

Both MMSE and MoCA were feasible in 621 (70.5%) patients. Factors independently associated with nonfeasibility were age (odds ratio [OR]: 1.05; 95% confidence interval [CI]: 1.02-1.08), IQCODE score (OR: 1.02; 95%CI: 1.00-1.04), and National Institutes of Health Stroke Scale (NIHSS) score (OR, 1.16; 95%CI, 1.12-1.20). Impaired MoCA (with a cut-off <26/30) performance was observed in 544 of 621 (87.6%) patients. Factors independently associated with cognitive impairment were age (OR: 1.06; 95%CI: 1.03-1.10) and NIHSS score (OR: 1.34; 95%CI: 1.14-1.57). Eighty percent of patients with normal MMSE scores had an impaired MoCA score (MMSE-MoCA mismatch). The differences were highest in the visuospatial (94.8% versus 65.3%; P < .0001), recall (76.6% versus 35.6%; P < .0001), abstraction (82.5% versus 49.8%; P < .0001), and language (72.3% versus 65.9%; P < .0001) domains between the normal MMSE and MoCA group and MMSE-MoCA mismatch group.

CONCLUSIONS

The MoCA can be particularly useful in patients with cognitive deficits undetectable on the MMSE in the acute stroke phase.

Reducing door-to-reperfusion time in acute stroke endovascular therapy using magnetic resonance imaging as a screening modality

Background

The feasibility of performing MRI first for patients with suspected hyperacute stroke in real-world practice has not been fully examined. Moreover, most past studies of reducing door-to-reperfusion time (DRT) in endovascular treatment (EVT) were conducted using CT. The aim of this study was to evaluate the feasibility of an MRI-first policy and to examine the effects of a quality improvement (QI) process for reducing DRT using MRI.

Methods

From January 2013 to December 2018, consecutive patients with acute stroke who came to hospital directly and were treated with emergent EVT were prospectively enrolled into the present study. In principle, MRI was performed first for patients with suspected acute stroke. A step-by-step QI process for decreasing DRT was adopted during this period. Time metrics for EVT were compared between specific time periods.

Results

A total of 180 patients (71 women; median age 76 years (range 69–64); National Institutes of Health Stroke Scale score 17 (range 10–23)) were included in the present study. More patients in the late phase were managed with the MRI-first policy (p<0.001). DRT (199 min in Phase 1, 135 min in Phase 2, 129 min in Phase 3, and 121 min in Phase 4, p<0.001) was significantly reduced across the phases. The percentage of patients with DRT <120 min increased significantly across time periods (p<0.001). Symptomatic intracerebral hemorrhage did not increase across phases (p=0.575).

Conclusion

An MRI-first policy was feasible, and DRT decreased considerably with a step-by-step QI process. This process may be applicable to other hospitals.

Accurate etiology diagnosis in patients with stroke and atrial fibrillation: A role for brain natriuretic peptide

BACKGROUND

Atrial fibrillation (AF) is the leading cause of cardioembolic stroke (CES), and patients with stroke and AF are frequently assumed to have CES. However, strokes presumably due to atherosclerotic pathophysiologies in large or small vessels can also occur in patients with AF. The aims of the present study were to clarify the prevalence of and factors related to a non-cardioembolic etiology in acute stroke patients with AF.

METHODS

From March 2011 through May 2017, consecutive acute ischemic stroke patients with AF were retrospectively recruited. The concomitant presence of non-cardioembolic features (small vessel occlusion [SVO] or large artery atherosclerosis [LAA]) on imaging was evaluated. The frequency of and factors associated with co-existing SVO/LAA features were assessed.

RESULTS

A total of 560 consecutive patients with AF and acute stroke (237 women; median age 78 [IQR 71-85] years; NIHSS score 9 [3-20]) were enrolled. Of these, 42 (7.5%) had co-existing SVO/LAA features. Multivariable logistic regression analysis showed that the brain natriuretic peptide level (BNP, OR 0.78, p = .030 per 100 pg/mL increase) was independently and negatively associated with co-existing SVO/LAA features and receiver operating characteristic curve analysis revealed the practical cut-off BNP value was 130 pg/mL (sensitivity 54% and specificity 68%).

CONCLUSION

SVO/LAA features were found in 7.5% of acute stroke patients with AF. A relatively low BNP level on admission was independently associated with co-existing SVO/LAA features. Thorough examination for a more appropriate etiology may be particularly necessary in acute stroke patients with AF and a relatively low BNP level.

Transplantation of human dental pulp stem cells ameliorates brain damage following acute cerebral ischemia

AIMS

Numerous experimental studies have shown that cellular therapy, including human dental pulp stem cells (DPSCs), is an attractive strategy for ischemic brain injury. Herein, we examined the effects of intravenous DPSC administration after transient middle cerebral artery occlusion in rats.

METHODS

Male Sprague-Dawley rats received a transient 90 min middle cerebral artery occlusion. DPSCs (1 × 10⁶ cells) or vehicle were administered via the femoral vein at 0 h or 3 h after ischemia-reperfusion. PKH26, a red fluorescent cell linker, was used to track the transplanted cells in the brain. Infarct volume, neurological deficits, and immunological analyses were performed at 24 h and 72 h after reperfusion.

RESULTS

PKH26-positive cells were observed more frequently in the ipsilateral than the contralateral hemisphere. DPSCs transplanted at 0 h after reperfusion significantly reduced infarct volume and reversed motor deficits at 24 h and 72 h recovery. DPSCs transplanted at 3 h after reperfusion also significantly reduced infarct volume and improved motor function compared with vehicle groups at 24 h and 72 h recovery. Further, DPSC transplantation significantly inhibited microglial activation and pro-inflammatory cytokine expression compared with controls at 72 h after reperfusion. Moreover, DPSCs attenuated neuronal degeneration in the cortical ischemic boundary area.

CONCLUSIONS

Systemic delivery of human DPSCs after reperfusion reduced ischemic damage and improved functional recovery in a rodent ischemia model, with a clinically relevant therapeutic window. The neuroprotective action of DPSCs may relate to the modulation of neuroinflammation during the acute phase of stroke.

Prior Direct Oral Anticoagulant Therapy is Related to Small Infarct Volume and No Major Artery Occlusion in Patients With Stroke and Non-Valvular Atrial Fibrillation

Background The aims of the present study were to investigate the relationships between prior direct oral anticoagulant ( DOAC ) therapy and infarct volume and the site of arterial occlusion in patients with acute ischemic stroke and non-valvular atrial fibrillation. Methods and Results From March 2011 through November 2016, consecutive patients with acute ischemic stroke in the middle cerebral artery territory and non-valvular atrial fibrillation were recruited. The infarct volume was assessed semi-automatically using initial diffusion-weighted imaging, and the arterial occlusion site was evaluated on magnetic resonance angiography. The effect of prior DOAC treatment on the site of arterial occlusion was assessed by multivariate ordinal logistic regression analysis. A total of 330 patients (149 women; median age 79 [quartiles 71-86] years; median National Institutes of Health Stroke Scale score 11 [4-21]) were enrolled. Of these, 239 were on no anticoagulant, 40 were undertreated with a vitamin K antagonist ( VKA ), 22 were sufficiently treated with VKA ( PT - INR ≥1.6), and 29 were on a DOAC before the acute ischemic stroke. The infarct volume on admission differed among the groups (median 14.5 [2.0-59.8] cm3 in patients with no anticoagulation, 24.8 [2.1-63.0] in undertreated VKA , 1.3 [0.3-13.5] in sufficient VKA , and 2.3 [0.5-21.0] in DOAC , P=0.001). Multivariate analysis showed that prior DOAC treatment was independently and negatively associated with more proximal artery occlusion (odds ratio [OR] 0.34, P=0.015), compared with no anticoagulant. Conclusions DOAC treatment before the event was associated with smaller infarct volume and decreased risk of greater proximal artery occlusion in acute ischemic stroke patients with non-valvular atrial fibrillation, compared with no anticoagulation.

Impact of Dental Pulp Stem Cells Overexpressing Hepatocyte Growth Factor after Cerebral Ischemia/Reperfusion in Rats

Hepatocyte growth factor (HGF) has neuroprotective effects against ischemia-induced injuries. Dental pulp stem cell (DPSC) transplantation attenuates tissue injury in the brain of rats with post-transient middle cerebral artery occlusion. We sought to determine whether DPSCs that overexpress HGF can enhance their therapeutic effects on brain damage post-ischemia/reperfusion injury. Treatment with DPSCs overexpressing HGF reduced infarct volumes compared to unmodified DPSC treatment at 3 and 7 days post-transient middle cerebral artery occlusion. The use of unmodified DPSCs and DPSCs overexpressing HGF was associated with improved motor function compared to that with administration of vehicle at 7 days post-transient middle cerebral artery occlusion. DPSCs overexpressing HGF significantly inhibited microglial activation and pro-inflammatory cytokine production along with suppression of neuronal degeneration. Post-reperfusion, DPSCs overexpressing HGF attenuated the decreases in tight junction proteins, maintained blood-brain barrier integrity, and increased microvessel density in peri-infarct areas. The administration of DPSCs overexpressing HGF during the acute phase of stroke increased their neuroprotective effects by modulating inflammation and blood-brain barrier permeability, thereby promoting improvements in post-ischemia/reperfusion brain injury.

AMPA Receptor Antagonist Perampanel Ameliorates Post-Stroke Functional and Cognitive Impairments

Perampanel (PER), a noncompetitive α-amino-3-hydroxy-5-methyl-4-isoxazole propionate receptor antagonist, clinically used for seizure control, has been reported to exert neuroprotective effects in experimental models of neurodegenerative diseases. However, few studies have investigated the therapeutic effects of PER in brain injury including stroke. Our aim was to investigate the neuroprotective potential of PER using a rat transient middle cerebral artery occlusion (MCAO) model. Sprague-Dawley rats underwent 90-min MCAO followed by intraperitoneal PER administration at a dose of 1.5 mg/kg. Infarct volumes, neurological deficits, and immunological analyses were performed at 7 days after MCAO. PER significantly reduced infarct volumes (p < 0.05) and improved motor function (p < 0.05) compared with vehicle. Immunological analysis showed that PER significantly inhibited microglial activation, pro-inflammatory cytokine expression, and oxidative stress compared with vehicle. Moreover, PER suppressed neurodegeneration in the cortical ischemic boundary zone, via downregulation of Bcl-2-associated x and upregulation of Bcl-extra-large with Akt activation. In addition, post-stroke secondary neuronal damage and cognitive impairments, using the Y-maze test, were assessed 30 days after MCAO. PER significantly improved spatial working memory, which was accompanied by hippocampal CA1 neuronal loss and cortical thinning, compared with vehicle. These results indicate that PER attenuates infarct volumes and motor function deficits possibly through its anti-inflammatory, antioxidant, and anti-apoptotic activities, mediated via activation of phosphatidylinositol 3-kinase (PI3K)/Akt pathways in the acute ischemic phase, and further ameliorates post-stroke cognitive impairments via the suppression of secondary neuronal damage in the chronic ischemic phase.

Abstract WMP74: Therapeutic Effect of Human Dental Pulp Stem Cells Overexpressing Hepatocyte Growth Factor in Experimental Ischemic Stroke

Objective: Human dental pulp stem cell (DPSC) is an attractive cell source because they can be easily obtained as medical waste without ethical and logistical problems. Transplantation of DPSC decreases tissue injury in the rat brain and enhances motor function recovery after the middle cerebral artery occlusion (MCAO). We aimed increasing therapeutic effects combining DPSC and ex vivo human hepatocyte growth factor (HGF) gene transfer with adeno-associated virus (AAV) vector.

Methods: Male Sprague-Dawley rats were subjected to transient 90 minute MCAO, followed by intravenous administration of 1 x 10 6 cells of DPSC, AAV-1/HGF transferred DPSC (DPSC/HGF) or vehicle immediately after reperfusion (each, n=8). Infarct volumes, neurological deficits and immunochemistry were assessed at 24 and 72 h after reperfusion. We also detected concentrations of TNF-α and IL-1β in the brain tissue extracts from the ischemic hemisphere by ELISA.

Results: Infarct volumes at 24 h after reperfusion were diminished in both DPSC (155.7 ± 35.6 mm 3 , p < 0.01) and DPSC/HGF (110.2 ± 34.7 mm 3 , p < 0.01) transplantation compared with vehicle (213.1 ± 29.1 mm 3 ). DPSC/HGF transplantation showed more reduction of infarct volume compared with DPSC (110.2 ± 34.7 mm 3 vs 155.7 ± 35.6 mm 3 , p < 0.05). Motor function recovery was also observed at 24 and 72 h by both DPSC and DPSC/HGF transplantation. Furthermore, we determined that DPSC/HGF transplantation significantly suppressed expression of Iba-1 and TNF-α compared with DPSC in the cortical ischemic boundary zone (p < 0.05, p < 0.01). Also, DPSC/HGF markedly decreased brain tissue TNF-α (11.5 ± 4.2 pg/ml) and IL-1β (22.2 ± 4.2 pg/ml) concentrations compared with vehicle (TNF-α, 54.6 ± 9.8 pg/ml, p < 0.01; IL-1β, 95.2 ± 9.8 pg/ml, p < 0.01) and DPSC (TNF-α, 26.8 ± 11.2 pg/ml, p < 0.05; IL-1β, 40.6 ± 11.2 pg/ml, p < 0.05) in the ischemic hemisphere. Both DPSC and DPSC/HGF group improved neuronal degeneration compared with vehicle (p < 0.05, p < 0.01).

Conclusions: These findings show that overexpression of HGF by AAV vector would enhance the neuroprotective effects of DPSC transplantation through the modulation of inflammation after acute ischemic stroke.

Low Free Triiodothyronine at Admission Predicts Poststroke Infection

BACKGROUND

Poststroke infection (PSI) is common and is usually associated with a severe prognosis. We investigated the association between PSI and thyroid hormones, which are critical to immune regulation, in patients with acute stroke.

METHODS

We retrospectively enrolled 520 consecutive patients with acute ischemic stroke (326 men; age, 71.9 ± 13.2 years) admitted to our department between September 2014 and June 2016. The impact of serum thyroid hormone levels measured at admission (thyroid-stimulating hormone [TSH], free triiodothyronine [FT3], and free thyroxine [FT4]) on the PSI was evaluated using multivariate logistic regression analysis.

RESULTS

We diagnosed 107 patients (20.6%; pneumonia, 65; urinary tract infection, 19; others, 23) with PSIs. While age (P <.001), body mass index (P = .0012), preadmission modified Rankin scale score (P = .0001), National Institutes of Health Stroke Scale score on admission (P <.001), admission FT3 level (P <.001), atrial fibrillation (P <.001), and ischemic heart disease (P = .0451) were significantly associated with PSI, we found no relationship among TSH levels, FT4 levels, and PSI occurrence. After multivariate adjustment, patients with PSIs were more frequently in the Q1 quartile (≤2.25 pg/mL) than in the Q2 (2.26-2.55 pg/mL; P = .0251), Q3 (2.56-2.89 pg/mL; P = .0007), or Q4 (≥2.90 pg/mL; P = .0010) quartiles of FT3 levels. Moreover, low FT3 levels (<2.29 pg/mL) were independently associated with PSI occurrence (P = .0013).

CONCLUSIONS

Low FT3 levels at admission are independently associated with PSI occurrence.

The Prevalence of and Factors Related to Vascular Hyperintensity on T1-Weighted Imaging in Acute Ischemic Stroke

BACKGROUND

Thrombus visualization in patients with acute ischemic stroke has been detected and reported using various imaging modalities. T1-weighted imaging (T1-WI) can depict thrombi as hyperintense signals within vessels. Moreover, in addition to thrombi, T1-WI hyperintensities in arteries may suggest arterial dissection. However, the frequency of and factors related to the T1-hyperintense vessel sign (T1-HVS) are not fully known. The aim of this study was to clarify the prevalence of and related factors for the T1-HVS in patients with acute ischemic stroke.

METHODS

From September 2014 through December 2015, consecutive acute ischemic stroke patients who were admitted to our stroke unit within 7 days from symptom onset were retrospectively recruited from the prospective registry. A T1-HVS was defined as the presence of a hyperintense signal, with intensity higher than surrounding brain, within the vessel lumen. Moreover, T1-HVSs were separated into filled T1-HVSs (hyperintensity fills whole vessel lumen) and non-filled T1-HVSs. The frequency of the T1-HVS and the timing of emersion and the relationship between the presence of the T1-HVS and arterial occlusion were assessed.

RESULTS

A total of 399 patients (139 women; median age 73 years; National Institutes of Health Stroke Scale score 3) were enrolled in the present study. Of these, 327 (82%) patients had T1-WI on admission. Two hundred and sixty-seven (67%) subjects had at least one follow-up T1-WI (median 6 days after admission), and 134 (34%) cases had ≥2 follow-up T1-WI examinations. The T1-HVS was observed in 18 patients during admission; therefore, the frequency of the T1-HVS in acute ischemic stroke patients was 4.5% (95% CI 2.5-6.5%). All but one (94%) of the T1-HVSs were first observed on follow-up imaging, and the median number of days from onset to T1-HVS appearance was 9. For patients having initial major artery occlusion and follow-up MRI (n = 95), sensitivity and specificity of the T1-HVS for persistent arterial occlusion on follow-up MR angiography were 22 and 100%, respectively. T1-HVS persisted for a few months and then normalized. Although there were no significant differences between filled and non-filled T1-HVS, more patients with non-filled T1-HVS had arterial dissection (43%) than those with filled T1-HVS (9%, p = 0.245).

CONCLUSION

The T1-HVS was observed in 4.5% of acute ischemic stroke patients. T1-HVSs appeared in the subacute phase in arteries with persistent occlusion and remained for a few months.

Mesenchymal Stem Cells Overexpressing Interleukin-10 Promote Neuroprotection in Experimental Acute Ischemic Stroke

Interleukin (IL)-10 is a contributing factor to neuroprotection of mesenchymal stem cell (MSC) transplantation after ischemic stroke. Our aim was to increase therapeutic effects by combining MSCs and ex vivo IL-10 gene transfer with an adeno-associated virus (AAV) vector using a rat transient middle cerebral artery occlusion (MCAO) model. Sprague-Dawley rats underwent 90 min MCAO followed by intravenous administration of MSCs alone or IL-10 gene-transferred MSCs (MSC/IL-10) at 0 or 3 hr after ischemia reperfusion. Infarct lesions, neurological deficits, and immunological analyses were performed within 7 days after MCAO. 0-hr transplantation of MSCs alone and MSC/IL-10 significantly reduced infarct volumes and improved motor function. Conversely, 3-hr transplantation of MSC/IL-10, but not MSCs alone, significantly reduced infarct volumes (p < 0.01) and improved motor function (p < 0.01) compared with vehicle groups at 72 hr and 7 days after MCAO. Immunological analysis showed that MSC/IL-10 transplantation significantly inhibits microglial activation and pro-inflammatory cytokine expression compared with MSCs alone. Moreover, overexpressing IL-10 suppressed neuronal degeneration and improved survival of engrafted MSCs in the ischemic hemisphere. These results suggest that overexpressing IL-10 enhances the neuroprotective effects of MSC transplantation by anti-inflammatory modulation and thereby supports neuronal survival during the acute ischemic phase.

Neuroprotective effects of clarithromycin against neuronal damage in cerebral ischemia and in cultured neuronal cells after oxygen-glucose deprivation

AIMS

Rats subjected to transient focal ischemia and cultured neuronal cells subjected to oxygen-glucose deprivation (OGD) were treated with clarithromycin (CAM) to evaluate the effects of CAM in protecting against neuronal damage.

MAIN METHODS

Sprague-Dawley rats were subjected to middle cerebral artery occlusion (MCAO) for 90min and then reperfused. Each animal was given an oral dose clarithromycin (CAM, 100mg/kg) or vehicle alone just after the ischemia was commenced. The infarct volume, edema index and neurological performance were assessed after 24 and 72h of reperfusion. The cerebral blood flow (CBF) was measured with an MRI system at 90min after MCAO. After 24 and 72h, oxidative stress (4-HNE, 8-OHdG) and inflammation (Iba-1, TNF-α) were assessed by immunohistochemical analyses and degenerative cells were assessed in the cortex by Fluoro-Jade C (FJC) labeling. The cultured neuronal cells were also used to examine the effects of CAM exposure on the viability of the cells after OGD.

KEY FINDINGS

CBF was unchanged between the two groups. Significant reductions of the infarct volume and edema index, an improved neurological deficit score, a significant suppression of 4-HNE and 8-OHdG expression, marked reductions of Iba-1 and TNF-α expression, and a significant reduction of FJC-positive cells were also observed in the CAM-treated animals at both time points. Treatment with 10μM and 100μM CAM in vitro significantly reduced cell death after OGD.

SIGNIFICANCE

CAM appears to provide antioxidant and anti-inflammatory effects and protect against neuronal damage after cerebral ischemia and OGD.

Multiple Cerebral Infarctions in a Patient with Adenomyosis on Hormone Replacement Therapy: A Case Report

A 59-year-old woman was admitted to our hospital because of repeated episodes of bilateral hand weakness. She had a 10-year history of combined estrogen-progestin therapy for menopausal symptoms. Magnetic resonance imaging on admission showed multiple hyperintense lesions in bilateral cerebral and cerebellar cortices on diffusion-weighted imaging. Transesophageal echocardiography showed thrombus formation on the aortic valve and moderate aortic insufficiency. Laboratory test demonstrated elevated CA125 (334.8 U/mL) and D-dimer (7.0 µg/mL) levels. Trousseau's syndrome (cancer-related hypercoagulation) was considered, but various examinations showed only uterine adenomyosis and no evidence of cancer. Multiple cerebral infarctions were considered to be caused by Trousseau's syndrome-like condition associated with uterine adenomyosis. CA125 and coagulation markers should be measured in adenomyosis patients treated with hormone replacement therapy, because a mucinous tumor and coagulation markers may be good markers for the risk of thromboembolism in such patients.

Neuroprotective effects of erythromycin on ischemic injury following permanent focal cerebral ischemia in rats

OBJECTIVE

This study aims to determine if erythromycin provides neuroprotective effects against ischemic injury following permanent focal cerebral ischemia.

METHODS

Sprague-Dawley rats were subjected to middle cerebral artery occlusion (MCAO). Each animal received a single subcutaneous injection of erythromycin lactobionate (EM, 50 mg/kg) or vehicle immediately after ischemia. The infarct volume, edema index and neurological performance were evaluated at 24 and 72 h after MCAO. The cerebral blood flow (CBF) was measured with an MRI system at 30 min after MCAO. TUNEL staining and immunohistochemical analyses for oxidative stress (4-HNE, 8-OHdG) and inflammation (Iba-1, TNF-α) in the cortex were conducted at 24 and 72 h after MCAO.

RESULTS

The CBF did not differ between the EM-treated and vehicle-treated groups. The EM treatment significantly reduced the infarct volume (p < 0.01) at 24 and 72 h after MCAO and significantly reduced the edema index (p < 0.01) at 24 h. The EM treatment significantly improved the neurological deficit scores (p < 0.05) at 24 and 72 h. EM also significantly suppressed the accumulation of 4-HNE (p < 0.01) and 8-OHdG (p < 0.01) and markedly reduced Iba-1 (p < 0.01) and TNF-α expression (p < 0.05) at both time points. The EM treatment significantly reduced TUNEL-positive cells (p < 0.01) at both time points.

CONCLUSION

These findings suggest that EM can protect against the neuronal damage caused by cerebral ischemia by alleviating inflammation and reducing oxidant stress.

Abstract W P90: Valproic Acid Ameliorates Ischemic Brain Injury in Hyperglycemic Rats with Permanent Middle Cerebral Occlusion

Background: Valproic acid (VPA) is widely used for the treatment of epilepsy in clinic. Some previous studies demonstrated that VPA ameliorated brain injury following experimental stroke. However, the effect of VPA in stroke model with comorbid conditions has not been fully studied. In this study, we investigated the effects of VPA in permanent ischemic stroke with hyperglycemia.

Methods: Male Sprague-Dawley rats were subjected to permanent middle cerebral artery occlusion according to a modification of the Tamura method. Hyperglycemia was induced by streptozotocin (STZ) injection 3 days before ischemia induction. The animals received a single injection of VPA immediately after the induction of ischemia. Vehicle-treated animals underwent the same procedure with physiological saline. Infarct volume, neurological deficits and immunohistological assessments were performed 3 days after ischemia.

Results: Hyperglycemia significantly enhanced the number of myeloperoxidase-positive cells, ionized calcium binding adapter molecule 1-positive cells, inducible nitric oxide synthase-positive cells, von Willebrand factor-positive cells, and Fluoro-Jade C-positive cells in the ischemic boundary zone, which was accompanied by increased infarct volume and neurological deficit compared with normoglycemia (p < 0.05; Figure). VPA significantly alleviated the aggravation of neurological deficit by suppressing these inflammation, endothelial injury, and neuronal degeneration compared with saline-treated group (p < 0.05; Figure).

Conclusions: Our results showed that VPA ameliorated neurological deficits through modulating the inflammatory responses and protecting endothelial damage, leading to reduced neuronal cell death following ischemia in STZ-induced hyperglycemic rats.

Neuroprotective effects of pretreatment with macrolide antibiotics on cerebral ischemia reperfusion injury

OBJECTIVE

This study aims to determine if macrolide antibiotics have neuroprotective effects against transient cerebral ischemia.

METHODS

Sprague-Dawley rats were subjected to cerebral ischemia for 90 minutes followed by 24 or 72 hours of reperfusion. An oral suspension of roxithromycin (RXM), clarithromycin (CAM), erythromycin (EM), azithromycin (AZM), or kitasamycin (INN) was given at 10 or 100 mg/kg for 7 days before ischemia. The infarct volume, edema volume, and neurological performance were evaluated after 24 and 72 hours of reperfusion. The cerebral blood flow (CBF) was measured with a magnetic resonance imaging (MRI) system after 90 minutes of ischemia. Another experiment was conducted to investigate how the ischemic injury was affected by the interval from the antibiotic pretreatment to the ischemia in rats pretreated with CAM.

RESULTS

Roxithromycin, CAM, AZM, and INN significantly reduced the infarct volume in the high-dose group after 24 and 72 hours of reperfusion. All of the agents significantly decreased the edema in the high-dose groups at 24 and 72 hours, while only CAM and AZM significantly reduced the edema volume in the low-dose groups at 24 hours. All of the macrolide antibiotics at the high dose significantly improved neurological deficit scores at 24 and 72 hours. There were no differences in the CBF between the vehicle and respective antibiotic groups. In the experiment examining the interval, the 24-hour interval group exhibited the strongest neuroprotective effect.

DISCUSSION

These results demonstrate that the macrolide antibiotics RXM, CAM, EM, AZM, and INN may confer neuroprotective effects against ischemic damage following cerebral ischemia without affecting the CBF.

Neuroprotective effects of erythromycin on cerebral ischemia reperfusion-injury and cell viability after oxygen-glucose deprivation in cultured neuronal cells

This study aims to determine if erythromycin has neuroprotective effects against transient ischemia and oxygen-glucose deprivation (OGD) in cultured neuronal cells. Sprague-Dawley rats were subjected to middle cerebral artery occlusion for 90 min, followed by reperfusion. The animals received a subcutaneous single injection of erythromycin lactobionate (EM, 50mg/kg) or vehicle immediately after ischemia. Infarct volume, edema index, and neurological performance were evaluated at 24 and 72 h after reperfusion. Immunohistochemical analyses for oxidative stress (4-HNE, 8-OHdG) and inflammation (Iba-1, TNF-α) were conducted in the cortex at 24h. Primary cortical neuronal cell cultures were prepared from the cerebral cortices of the animals and then subjected to OGD for 3h. Ten or 100 μM EM was added before OGD to determine the effect of EM on cell viability after OGD. EM significantly reduced infarct volume (p<0.01) and edema volume (p<0.05) and improved neurological deficit scores (p<0.05) at 24 and 72 h. EM significantly suppressed the accumulation of 4-HNE (p<0.01) and 8-OHdG (p<0.01) and markedly reduced Iba-1 (p<0.01) and TNF-α expression (p<0.01). Treatment with 100 μM EM in vitro significantly reduced cell death after OGD. EM reduces neuronal damage following cerebral ischemia and OGD and may have antioxidant and anti-inflammatory effects.

Effect of repeated allogeneic bone marrow mononuclear cell transplantation on brain injury following transient focal cerebral ischemia in rats

AIMS

Transplantation of bone marrow mononuclear cells (BMMCs) exerts neuroprotection against cerebral ischemia. We examined the therapeutic timepoint of allogeneic BMMC transplantation in a rat model of focal cerebral ischemia, and determined the effects of repeated transplantation outside the therapeutic window.

MAIN METHODS

Male Sprague-Dawley rats were subjected to 90 minute focal cerebral ischemia, followed by intravenous administration of 1 × 10(7) allogeneic BMMCs or vehicle at 0, 3 or 6 h after reperfusion or 2 × 10(7) BMMCs 6 h after reperfusion. Other rats administered 1 × 10(7) BMMCs at 6 h after reperfusion received additional BMMC transplantation or vehicle 9 h after reperfusion. Infarct volumes, neurological deficit scores and immunohistochemistry were evaluated 24 or 72 h after reperfusion.

KEY FINDINGS

Infarct volumes at 24 h were significantly decreased in transplantation rats at 0 and 3 h, but not at 6 h, after reperfusion, compared to vehicle-treatment. Even high dose BMMC transplantation at 6h after reperfusion was ineffective. Repeated BMMC transplantation at 6 and 9h after reperfusion reduced infarct volumes and significantly improved neurological deficit scores at 24 and 72 h. Immunohistochemistry showed repeated BMMC transplantation reduced ionized calcium-binding adapter molecule 1, 4-hydroxy-2-nonenal and 8-hydroxydeoxyguanosine expression at 24 and 72 h after reperfusion.

SIGNIFICANCE

Intravenous allogeneic BMMCs were neuroprotective following transient focal cerebral ischemia, and the therapeutic time window of BMMC transplantation was >3 h and <6 h after reperfusion in this model. Repeated transplantation at 6 and 9 h after reperfusion suppressed inflammation and oxidative stress in ischemic brains, resulting in improved neuroprotection.

Continuous oral administration of atorvastatin ameliorates brain damage after transient focal ischemia in rats

AIMS

Pre-treatment with statins is known to ameliorate ischemic brain damage after experimental stroke, and is independent of cholesterol levels. We undertook pre- vs post-ischemic treatment with atorvastatin after focal cerebral ischemia in rats.

MAIN METHODS

Male Sprague-Dawley rats underwent transient 90-min middle cerebral artery occlusion (MCAO). Atorvastatin (20mg/kg/day) or vehicle was administered orally. Rats were divided into vehicle-treated, atorvastatin pre-treatment, atorvastatin post-treatment, and atorvastatin continuous-treatment groups. In the pre-treatment, rats were given atorvastatin or vehicle for 7 days before MCAO. In the post-treatment, rats received atorvastatin or vehicle for 7 days after MCAO. Measurement of infarct volume, as well as neurological and immunohistochemical assessments, were done 24h and 7 days after reperfusion.

KEY FINDINGS

Each atorvastatin-treated group demonstrated significant reductions in infarct and edema volumes compared with the vehicle-treated group 24h after reperfusion. Seven days after reperfusion, infarct volumes in the post-treatment group and continuous-treatment group (but not the pre-treatment group) were significantly smaller than in the vehicle-treated group. Only the continuous-treatment group had significantly improved neurological scores 7 days after reperfusion compared with the vehicle group. Post-treatment and continuous-treatment groups had significantly decreased lipid peroxidation, oxidative DNA damage, microglial activation, expression of tumor necrosis factor-alpha, and neuronal damage in the cortical ischemic boundary area after 7 days of reperfusion.

SIGNIFICANCE

These results suggest that continuous oral administration (avoiding withdrawal) with statins after stroke may reduce the extent of post-ischemic brain damage and improve neurological outcome by inhibiting oxidative stress and inflammatory responses.

Therapeutic impact of eicosapentaenoic acid on ischemic brain damage following transient focal cerebral ischemia in rats

Long-chain n-3 polyunsaturated fatty acids, such as eicosapentaenoic acid (EPA), have been shown to reduce ischemic neuronal injury. We investigated the effects of ethyl-EPA (EPA-E) on ischemic brain damage using a rat transient focal cerebral ischemia model. Male Sprague-Dawley rats (n=105) were subjected to 90 min of focal cerebral ischemia. EPA-E (100mg/kg/day) or vehicle was administered once a day for 3, 5 or 7 days prior to ischemia. Different withdrawal intervals of 3, 5, and 7 days prior to ischemia following 7-day pretreatment with EPA-E or vehicle were also examined. In addition, post-ischemic administration of EPA-E was investigated. Pretreatment with EPA-E for 7 and 5 days, but not 3 days, showed significant infarct volume reduction and neurological improvements when compared with vehicle pretreatment. In addition, withdrawal of EPA-E administration for 3 days, but not 5 and 7 days, also demonstrated significant infarct volume reduction and neurological improvements when compared with vehicle treatment. Post-ischemic treatment of EPA-E did not show any neuroprotection. Immunohistochemistry revealed that 7-day pretreatment with EPA-E significantly reduced cortical expression of 8-hydroxydeoxyguanosine (maker for oxidative DNA damage), 4-hydroxy-2-nonenal (maker for lipid peroxidation), phosphorylated adducin (marker for Rho-kinase activation) and von Willebrand factor (endothelial marker) when compared with vehicle pretreatment. In addition, phosphorylated adducin expression co-localized with von Willebrand factor immunoreactivity. The present study established the neuroprotective effect of EPA-E on ischemic brain damage following transient focal cerebral ischemia in rats, which may be involved in the suppression of oxidative stress and endothelial Rho-kinase activation.

Involvement of mitogen-activated protein kinase pathways in expression of the water channel protein aquaporin-4 after ischemia in rat cortical astrocytes

Brain edema after ischemic brain injury is a key determinant of morbidity and mortality. Aquaporin-4 (AQP4) plays an important role in water transport in the central nervous system and is highly expressed in brain astrocytes. However, the AQP4 regulatory mechanisms are poorly understood. In this study, we investigated whether mitogen-activated protein kinases (MAPKs), which are involved in changes in osmolality, might mediate AQP4 expression in models of rat cortical astrocytes after ischemia. Increased levels of AQP4 in primary cultured astrocytes subjected to oxygen-glucose deprivation (OGD) and 2 h of reoxygenation were observed, after which they immediately decreased at 0 h of reoxygenation. Astrocytes exposed to OGD injury had significantly increased phosphorylation of three kinds of MAPKs. Treatment with SB203580, a selective p38 MAPK inhibitor, or SP600125, a selective c-Jun N-terminal kinase inhibitor, significantly attenuated the return of AQP4 to its normal level, and SB203580, but not SP600125, significantly decreased cell death. In an in vivo study, AQP4 expression was upregulated 1-3 days after reperfusion, which was consistent with the time course of p38 phosphorylation and activation, and decreased by the p38 inhibition after transient middle cerebral artery occlusion (MCAO). These results suggest that p38 MAPK may regulate AQP4 expression in cortical astrocytes after ischemic injury.

FK506 ameliorates oxidative damage and protects rat brain following transient focal cerebral ischemia

OBJECTIVE

The immunosuppressant FK506 (tacrolimus) is neuroprotective in experimental models of cerebral ischemia. However, the precise mechanisms underlying this neuroprotection remain unknown. In the present study, we hypothesized that FK506 treatment could protect rat brain from oxidative injuries through antioxidative and anti-inflammatory pathways after ischemia-reperfusion injury.

METHODS

Sprague-Dawley rats were subjected to middle cerebral artery occlusion for 120 minutes, followed by reperfusion. Animals received a single injection of FK506 (0·3 mg/kg) or vehicle intravenously at 30 minutes after ischemic induction. Infarct volume and neurological performance were evaluated at 24 hours after reperfusion. Immunohistochemical analysis for 4-hydroxy-2-nonenal (4-HNE), 8-hydroxy-deoxyguanosine (8-OHdG), ionized calcium-binding adapter molecule 1 (Iba-1), and tumor necrosis factor-alpha (TNF-alpha) were conducted at 24 hours after reperfusion.

RESULTS

FK506 significantly reduced infarct volume (61·7%; P=0·01) and improved neurological deficit scores (P<0·05) 24 hours after reperfusion compared to vehicle. In FK506-treated rats, accumulation of 4-HNE (P<0·01) and 8-OHdG (P<0·01) was significantly suppressed in the cerebral cortex 24 hours after reperfusion. In addition, FK506 markedly reduced microglial activation (P<0·01) and TNF-alpha expression (P<0·01).

DISCUSSION

These results demonstrate that FK506 may have antioxidant as well as anti-inflammatory effects and reduces ischemic damage following cerebral infarction.

Potential role of PUMA in delayed death of hippocampal CA1 neurons after transient global cerebral ischemia

BACKGROUND AND PURPOSE

p53-upregulated modulator of apoptosis (PUMA), a BH3-only member of the Bcl-2 protein family, is required for p53-dependent and -independent forms of apoptosis. PUMA localizes to mitochondria and interacts with antiapoptotic Bcl-2 and Bcl-X(L) or proapoptotic Bax in response to death stimuli. Although studies have shown that PUMA is associated with pathomechanisms of cerebral ischemia, clearly defined roles for PUMA in ischemic neuronal death remain unclear. The purpose of this study was to determine potential roles for PUMA in cerebral ischemia.

METHODS

Five minutes of transient global cerebral ischemia (tGCI) were induced by bilateral common carotid artery occlusion combined with hypotension.

RESULTS

PUMA was upregulated in vulnerable hippocampal CA1 neurons after tGCI as shown by immunohistochemistry. In Western blot and coimmunoprecipitation analyses, PUMA localized to mitochondria and was bound to Bcl-X(L) and Bax in the hippocampal CA1 subregion after tGCI. PUMA upregulation was inhibited by pifithrin-alpha, a specific inhibitor of p53, suggesting that PUMA is partly controlled by the p53 transcriptional pathway after tGCI. Furthermore, reduction in oxidative stress by overexpression of copper/zinc superoxide dismutase, which is known to be protective of vulnerable ischemic hippocampal neurons, inhibited PUMA upregulation and subsequent hippocampal CA1 neuronal death after tGCI.

CONCLUSIONS

These results imply a potential role for PUMA in delayed CA1 neuronal death after tGCI and that it could be a molecular target for therapy.

Reduction in oxidative stress by superoxide dismutase overexpression attenuates acute brain injury after subarachnoid hemorrhage via activation of Akt/glycogen synthase kinase-3beta survival signaling

Recent studies have revealed that oxidative stress has detrimental effects in several models of neurodegenerative diseases, including subarachnoid hemorrhage (SAH). However, how oxidative stress affects acute brain injury after SAH remains unknown. We have previously reported that overexpression of copper/zinc-superoxide dismutase (SOD1) reduces oxidative stress and subsequent neuronal injury after cerebral ischemia. In this study, we investigated the relationship between oxidative stress and acute brain injury after SAH using SOD1 transgenic (Tg) rats. SAH was produced by endovascular perforation in wild-type (Wt) and SOD1 Tg rats. Apoptotic cell death at 24 h, detected by a cell death assay, was significantly decreased in the cerebral cortex of the SOD1 Tg rats compared with the Wt rats. The mortality rate at 24 h was also significantly decreased in the SOD1 Tg rats. A hydroethidine study demonstrated that superoxide anion production after SAH was reduced in the cerebral cortex of the SOD1 Tg rats. Moreover, phosphorylation of Akt and glycogen synthase kinase-3beta (GSK3beta), which are survival signals in apoptotic cell death, was more enhanced in the cerebral cortex of the SOD1 Tg rats after SAH using Western blot analysis and immunohistochemistry. We conclude that reduction in oxidative stress by SOD1 overexpression may attenuate acute brain injury after SAH via activation of Akt/GSK3beta survival signaling.

Bad as a converging signaling molecule between survival PI3-K/Akt and death JNK in neurons after transient focal cerebral ischemia in rats

Bad, a proapoptotic Bcl-2 family protein, plays a critical role in determining cell death/survival. The phosphatidylinositol 3-kinase (PI3-K)/Akt pathway and the c-Jun N-terminal kinase (JNK) pathway are thought to be involved in regulation of Bad. Therefore, the present study was performed to clarify the role of Bad as a common target of the PI3-K/Akt and JNK pathways after transient focal cerebral ischemia (tFCI) in rats. We found that Akt activity increased at 3 h and then decreased, whereas JNK activity increased 7 to 24 h in the peripheral area after tFCI. Administration of LY294002, a PI3-K-specific inhibitor, exacerbated DNA fragmentation, whereas administration of SP600125, a JNK-specific inhibitor, attenuated it. Inhibited by LY294002, phospho-Bad (Ser136) expression increased in the peripheral area 3 h after tFCI, with suppression of Akt activity. Furthermore, phospho-Bad (Ser136) and phospho-Akt (Ser473) were colocalized. Decreases in phospho-Bad (Ser136) and Bad/14-3-3 dimerization and increases in Bcl-X(L)/Bad or Bcl-2/Bad dimerization observed 7 to 24 h after tFCI, were prevented by SP600125 administration, with inhibition of JNK activity. The present study indicates that signal predominance varies from PI3-K/Akt-mediated survival signaling to JNK-mediated death signaling with the development of neuronal damage in the peripheral area after tFCI. This study also suggests that PI3-K/Akt has a role in Bad inactivation, whereas the JNK pathway is involved in Bad activation. We conclude that Bad may be an integrated checkpoint of PI3-K/Akt-mediated survival signaling and JNK-mediated death signaling and that it contributes to cell fate in the peripheral area after cerebral ischemia.

Influence of hyperglycemia on oxidative stress and matrix metalloproteinase-9 activation after focal cerebral ischemia/reperfusion in rats: relation to blood-brain barrier dysfunction

BACKGROUND AND PURPOSE

Hyperglycemia is linked to a worse outcome after ischemic stroke. Among the manifestations of brain damage caused by ischemia are blood-brain barrier (BBB) disruption and edema formation. Oxidative stress and matrix metalloproteinase-9 (MMP-9) activation are implicated in BBB dysfunction after ischemia/reperfusion injury. Our present study was designed to clarify the relation among hyperglycemia, oxidative stress, and MMP-9 activation associated with BBB dysfunction after transient focal cerebral ischemia (tFCI).

METHODS

We used a model of 60 minutes of middle cerebral artery occlusion on the following animals: normoglycemic wild-type rats, wild-type rats with hyperglycemia induced by streptozotocin, and human copper/zinc superoxide dismutase (SOD1) transgenic rats with streptozotocin-induced hyperglycemia. We evaluated edema volume, Evans blue leakage, and oxidative stress, such as the carbonyl groups and oxidized hydroethidine (HEt), SOD activity, and gelatinolytic activity, including MMP-9.

RESULTS

Hyperglycemia significantly increased edema volume and Evans blue leakage. Moreover, it enhanced the levels of the carbonyl groups, the oxidized HEt signals, and MMP-9 activity after tFCI without alteration in SOD activity. Gelatinolytic activity and oxidized HEt signals had a clear spatial relation in the hyperglycemic rats. SOD1 overexpression reduced the hyperglycemia-enhanced Evans blue leakage and MMP-9 activation after tFCI.

CONCLUSIONS

Hyperglycemia increases oxidative stress and MMP-9 activity, exacerbating BBB dysfunction after ischemia/reperfusion injury. Superoxide overproduction may be a causal link among hyperglycemia, MMP-9 activation, and BBB dysfunction.

Activation of the Akt/GSK3beta signaling pathway mediates survival of vulnerable hippocampal neurons after transient global cerebral ischemia in rats

Recent studies have revealed that the phosphatidylinositol 3-kinase (PI3-K) pathway is involved in apoptotic cell death after experimental cerebral ischemia. The serine-threonine kinase, Akt, functions in the PI3-K pathway and prevents apoptosis by phosphorylation at Ser473 after a variety of cell death stimuli. After phosphorylation, activated Akt inactivates other apoptogenic factors, including glycogen synthase kinase-3beta (GSK3beta), thereby inhibiting cell death. However, the role of Akt/GSK3beta signaling in the delayed death of hippocampal neurons in the CA1 subregion after transient global cerebral ischemia (tGCI) has not been clarified. Transient global cerebral ischemia for 5 mins was induced by bilateral common carotid artery occlusion combined with hypotension. Western blot analysis showed a significant increase in phospho-Akt (Ser473) and phospho-GSK3beta (Ser9) in the hippocampal CA1 subregion after tGCI. Immunohistochemistry showed that expression of phospho-Akt (Ser473) and phospho-GSK3beta (Ser9) was markedly increased in the vulnerable CA1 subregion, but not in the ischemic-tolerant CA3 subregion. Double staining with phospho-GSK3beta (Ser9) and terminal deoxynucleotidyl transferase-mediated uridine 5'-triphosphate-biotin nick end labeling showed different cellular distributions in the CA1 subregion 3 days after tGCI. Phosphorylation of Akt and GSK3beta was prevented by LY294002, a PI3-K inhibitor, which facilitated subsequent DNA fragmentation 3 days after tGCI. Moreover, transgenic rats that overexpress copper/zinc-superoxide dismutase, which is known to be neuroprotective against delayed hippocampal CA1 injury after tGCI, had enhanced and persistent phosphorylation of both Akt and GSK3beta after tGCI. These findings suggest that activation of the Akt/GSK3beta signaling pathway may mediate survival of vulnerable hippocampal CA1 neurons after tGCI.

Mitochondrial translocation of p53 mediates release of cytochrome c and hippocampal CA1 neuronal death after transient global cerebral ischemia in rats

Although p53 is a key modulator of cellular stress responses, the mechanism of p53-mediated apoptosis is ambiguous. p53 can mediate apoptosis in response to death stimuli by transcriptional activation of proapoptotic genes and transcriptional-independent mechanisms. Recent studies have shown that the p53 protein can directly induce permeabilization of the outer mitochondrial membrane by forming a inhibitory complex with a protective Bcl-2 family protein, resulting in cytochrome c release. However, how the mitochondrial p53 pathway mediates neuronal apoptosis after cerebral ischemia remains unclear. We examined the interaction between the mitochondrial p53 pathway and vulnerable hippocampal CA1 neurons in rats using a transient global cerebral ischemia (tGCI) model. Western blot analysis and immunofluorescent staining revealed mitochondrial p53 translocation after tGCI in the hippocampal CA1 neurons. Coimmunoprecipitation revealed that translocated p53 bound to Bcl-X(L) in the mitochondrial fraction. To examine the effect of a specific p53 inhibitor on the mitochondrial p53 pathway and apoptotic cell death after tGCI, we intravenously administered pifithrin-alpha (PFT). Mitochondrial p53 translocation and interaction between p53 and Bcl-X(L) were prevented by treatment with PFT. Moreover, cytochrome c release from mitochondria and subsequent apoptotic CA1 neuronal death were decreased with PFT treatment. These results suggest that the mitochondrial p53 pathway is one of the novel mechanisms mediating delayed death of vulnerable hippocampal CA1 neurons after tGCI.

Akt/GSK3beta survival signaling is involved in acute brain injury after subarachnoid hemorrhage in rats

BACKGROUND AND PURPOSE

Apoptotic cell death is associated with acute brain injury after subarachnoid hemorrhage (SAH). The Akt/glycogen synthase kinase-3beta (GSK3beta) pathway plays an important role in the cell death/survival pathway after a variety of cell death stimuli. However, its role in acute brain injury after SAH remains unknown.

METHODS

We used an endovascular perforation model of SAH in rats. Phospho-Akt and phospho-GSK3beta expression was examined by Western blot analysis and immunohistochemistry. Terminal deoxynucleotidyl transferase-mediated uridine 5'-triphosphate-biotin nick end-labeling (TUNEL) and a cell death assay were used for detection of apoptosis. We administered LY294002 to examine the role of the Akt/GSK3beta pathway in the phosphoinositide 3-kinase pathway after SAH.

RESULTS

Phosphorylation of Akt and GSK3beta was accelerated after SAH. In the cerebral cortex, where acute brain injury was the most severe, phosphorylation of these proteins was observed in the early phase after SAH. Cortical neurons with continuous Akt phosphorylation did not colocalize with TUNEL-positive cells at 24 hours. LY294002 reduced Akt and GSK3beta phosphorylation and increased brain injury after SAH.

CONCLUSIONS

The present study suggests that the Akt/GSK3beta pathway might be involved in neuronal survival in acute brain injury after SAH.