The cytosolic antioxidant, copper/zinc superoxide dismutase, attenuates blood-brain barrier disruption and oxidative cellular injury after photothrombotic cortical ischemia in mice

Blood-brain Barrier and Neurovascular Unit Dysfunction in Parkinson's Disease: From Clinical Insights to Pathogenic Mechanisms and Novel Therapeutic Approaches

The blood-brain barrier (BBB) plays a crucial role in the central nervous system by tightly regulating the influx and efflux of biological substances between the brain parenchyma and peripheral circulation. Its restrictive nature acts as an obstacle to protect the brain from potentially noxious substances such as blood-borne toxins, immune cells, and pathogens. Thus, the maintenance of its structural and functional integrity is vital in the preservation of neuronal function and cellular homeostasis in the brain microenvironment. However, the barrier's foundation can become compromised during neurological or pathological conditions, which can result in dysregulated ionic homeostasis, impaired transport of nutrients, and accumulation of neurotoxins that eventually lead to irreversible neuronal loss. Initially, the BBB is thought to remain intact during neurodegenerative diseases, but accumulating evidence as of late has suggested the possible association of BBB dysfunction with Parkinson's disease (PD) pathology. The neurodegeneration occurring in PD is believed to stem from a myriad of pathogenic mechanisms, including tight junction alterations, abnormal angiogenesis, and dysfunctional BBB transporter mechanism, which ultimately causes altered BBB permeability. In this review, the major elements of the neurovascular unit (NVU) comprising the BBB are discussed, along with their role in the maintenance of barrier integrity and PD pathogenesis. We also elaborated on how the neuroendocrine system can influence the regulation of BBB function and PD pathogenesis. Several novel therapeutic approaches targeting the NVU components are explored to provide a fresh outlook on treatment options for PD.

Blood-brain barrier permeability in the ischemic stroke: An update

Stroke is the second leading cause of death globally and the major cause of long-term disability. Among the types of strokes, ischemic stroke, which occurs due to obstruction of blood vessels responsible for cerebral irrigation, is considered the most prevalent, accounting for approximately 86 % of all stroke cases. This interruption of blood supply leads to a critical pathophysiological mechanism, including oxidative stress and neuroinflammation which are responsible for structural alterations of the blood-brain barrier (BBB). The increased BBB permeability associated with cerebral ischemia-reperfusion may contribute to a worse outcome after stroke. Thus, this narrative review aims to update the pathophysiological mechanisms involved in the increase in BBB permeability and to list the possible therapeutic strategies.

Role of Glial Cell-Derived Oxidative Stress in Blood-Brain Barrier Damage after Acute Ischemic Stroke

The integrity of the blood-brain barrier (BBB) is mainly maintained by endothelial cells and basement membrane and could be regulated by pericytes, neurons, and glial cells including astrocytes, microglia, oligodendrocytes (OLs), and oligodendrocyte progenitor cells (OPCs). BBB damage is the main pathological basis of hemorrhage transformation (HT) and vasogenic edema after stroke. In addition, BBB damage-induced HT and vasogenic edema will aggravate the secondary brain tissue damage. Of note, after reperfusion, oxidative stress-initiated cascade plays a critical role in the BBB damage after acute ischemic stroke (AIS). Although endothelial cells are the target of oxidative stress, the role of glial cell-derived oxidative stress in BBB damage after AIS also should receive more attention. In the current review, we first introduce the physiology and pathophysiology of the BBB, then we summarize the possible mechanisms related to BBB damage after AIS. We aim to characterize the role of glial cell-derived oxidative stress in BBB damage after AIS and discuss the role of oxidative stress in astrocytes, microglia cells and oligodendrocytes in after AIS, respectively.

Inflammation Mediated Epileptogenesis as Possible Mechanism Underlying Ischemic Post-stroke Epilepsy

Post-stroke Epilepsy (PSE) is one of the most common forms of acquired epilepsy, especially in the elderly population. As people get increasingly older, the number of stroke patients is expected to rise and concomitantly the number of people with PSE. Although many patients are affected by post-ischemic epileptogenesis, not much is known about the underlying pathomechanisms resulting in the development of chronic seizures. A common hypothesis is that persistent neuroinflammation and glial scar formation cause aberrant neuronal firing. Here, we summarize the clinical features of PSE and describe in detail the inflammatory changes after an ischemic stroke as well as the chronic changes reported in epilepsy. Moreover, we discuss alterations and disturbances in blood-brain-barrier leakage, astrogliosis, and extracellular matrix changes in both, stroke and epilepsy. In the end, we provide an overview of commonalities of inflammatory reactions and cellular processes in the post-ischemic environment and epileptic brain and discuss how these research questions should be addressed in the future.

Soy isoflavones ameliorate the cognitive dysfunction of Goto-Kakizaki rats by activating the Nrf2-HO-1 signalling pathway

Soy isoflavones (SIF) are soybean phytochemicals that are considered to be biologically active components that protect from neurodegenerative diseases. In this study, the therapeutic effect of SIF was evaluated in a diabetic Goto-Kakizaki (GK) rat model. Twenty male GK rats were randomly divided into diabetes mellitus (DM) model group and SIF+DM group (n=10 in each group). Twenty age-matched male Wistar rats were randomly divided into control group (CON group) and CON+SIF group, with 10 rats in each group. The learning and memory functions of the animals were determined by the Morris water maze (MWM) test. Hematoxylin-eosin staining (HE) was performed to examine pyramidal neuron loss in the CA1 area of the hippocampus. Markers of oxidative stress (OS) were measured to evaluate oxidative stress-mediated injury. RT-PCR and western blotting were used to analyze the expression of nuclear factorerythroid2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1) and NAD(P)H dehydrogenase quinone1 (NQO1). Treatment with SIF for 4 weeks alleviated the cognitive dysfunction of the GK rats as determined by the MWM test. Moreover, SIF treatment also reduced diabetes-related oxidative reactions. In addition, SIF enhanced the expression of Nrf2, HO-1 and NQO1, suggesting a potential antioxidation mechanism for the effect of SIF. These findings suggest that SIF can be considered candidates for inhibiting the progression of diabetes-induced cognitive dysfunction, provide novel insights into the antioxidant effect of SIF and further strengthen the link between oxidative stress and diabetes.

The Role of Transient Receptor Potential Channels in Blood-Brain Barrier Dysfunction after Ischemic Stroke

Stroke is the leading cause of long-term disability, demanding an ever-increasing need to find treatment. Transient receptor potential (TRP) channels are nonselective Ca²⁺-permeable channels, among which TRPC, TRPM, and TRPV are widely expressed in the brain. Dysfunction of the blood brain barrier (BBB) is a core feature of stroke and is associated with severity of injury. As studies have shown, TRP channels influence various neuronal functions by regulating the BBB. Here, we briefly review the role of TRP channel in the BBB dysfunction after stroke, and explore the therapeutic potential of TRP-targeted therapy.

Methylene blue post-treatment improves hypoxia-ischemic recovery in a neonatal rat model

Recent work suggested that methylene blue (MB) has beneficial effects in a variety of neurological disorders, while its role in neonatal hypoxic-ischemic (HI) encephalopathy is still unclear. The current study was designed to investigate the effects of MB on HI-induced brain damage and its underlying mechanisms. The results showed that MB treatment can strongly attenuate HI-induced brain loss and neuronal damage in the cortex and hippocampus of neonatal rats. Further mechanistic analysis suggested that MB treatment was able to significantly reduce blood-brain barrier disruption after HI insult. In addition, MB profoundly inhibited microglia and astrocyte activation and the pro-inflammatory cytokines production in neonatal cortex and hippocampus after HI. Further, MB treatment resulted in dramatic suppression of oxidative damage, as evidenced by robustly decreased DHE and protein carbonyls levels in HI brain. Moreover, MB strongly preserved mitochondrial function by repressing HI-induced mitochondrial fragmentation, and the following neuronal death in cortex and hippocampus. Finally, behavioral tests revealed that MB significantly improved the spatial reference memory and motor coordination of neonatal HI rats. Taken together, these findings demonstrate that the mechanisms behind neuroprotective actions of methylene blue are multifactorial, including suppression of oxidative stress and neuroinflammation, restoration of mitochondrial function, as well as attenuation of blood-brain barrier disruption. Our study might provide further directions for MB as a promising option in neonatal HI encephalopathy therapy.

New PAR1 Agonist Peptide Demonstrates Protective Action in a Mouse Model of Photothrombosis-Induced Brain Ischemia

Protease-activated receptors (PARs) are involved not only in hemostasis but also in the development of ischemic brain injury. In the present work, we examined in vivo effects of a new peptide (AP9) composing Asn⁴⁷-Phen⁵⁵ of PAR1 “tethered ligand” generated by activated protein C. We chose a mouse model of photothrombosis (PT)-induced ischemia to assess AP9 effects in vivo. To reveal the molecular mechanism of AP9 action, mice lacking β-arrestin-2 were used. AP9 was injected intravenously once 10 min before PT at doses of 0.2, 2, or 20 mg/kg, or twice, that is, 10 min before and 1 h after PT at a dose of 20 mg/kg. Lesion volume was measured by magnetic resonance imaging and staining of brain sections with tetrazolium salt. Neurologic deficit was estimated using the cylinder and the grid-walk tests. Blood–brain barrier (BBB) disruption was assessed by Evans blue dye extraction. Eosin-hematoxylin staining and immunohistochemical staining were applied to evaluate the number of undamaged neurons and activated glial cells in the penumbra. A single administration of AP9 (20 mg/kg), as well as its two injections (20 mg/kg), decreased brain lesion volume. A double administration of AP9 also reduced BBB disruption and neurological deficit in mice. We did not observe the protective effect of AP9 in mice lacking β-arrestin-2 after PT. Thus, we demonstrated for the first time protective properties of a PAR1 agonist peptide, AP9, in vivo. β-Arrestin-2 was required for the protective action of AP9 in PT-induced brain ischemia.

Methods for detection of brain injury after photothrombosis-induced ischemia in mice: Characteristics and new aspects of their application

BACKGROUND

Photothrombosis is a minimally invasive method for induction of cortical ischemia. However, different ways of applying some methods to assess photothrombosis-induced damage need to be developed.

NEW METHODS

We applied the tongue protrusion test and H&E staining of brain sections to detect ischemic damage after photothrombosis. Evaluation of the local status of the BBB using Evans blue dye was proposed. We also assessed the sensitivity of the grid-walk test. Moreover, we examined the interchangeability of MRI and TTC staining to measure lesion volume.

RESULTS

We evaluated ischemic outcomes at 24 h after photothrombosis in mice. The tongue protrusion test did not reveal impairments of the neurological status whereas the grid-walk test showed the high sensitivity. Using histological techniques, we determined the reduction in the number of neurons with normal morphology in the penumbra. 3D reconstruction of the brain, which reflected Evans blue dye distribution in the nervous tissue, revealed BBB disruption in areas remote from the ischemic core. We also showed the strong correlation between damage volumes assessed by MRI and TTC staining.

COMPARISON WITH EXISTING METHODS

The present work demonstrates the efficacy of the classical histological approach and TTC staining that are more affordable than MRI and immunohistochemical methods. Detection of 3D distribution of Evans blue dye in the brain in contrast to its total extraction reveals BBB damage in details.

CONCLUSIONS

We proposed the simple methods for describing the severity of brain ischemia at the cellular and whole organism levels without significant labor and financial expenditures.

Risperidone Treatment after Transient Ischemia Induces Hypothermia and Provides Neuroprotection in the Gerbil Hippocampus by Decreasing Oxidative Stress

Compelling evidence from preclinical and clinical studies has shown that mild hypothermia is neuroprotective against ischemic stroke. We investigated the neuroprotective effect of post-risperidone (RIS) treatment against transient ischemic injury and its mechanisms in the gerbil brain. Transient ischemia (TI) was induced in the telencephalon by bilateral common carotid artery occlusion (BCCAO) for 5 min under normothermic condition (37 ± 0.2 °C). Treatment of RIS induced hypothermia until 12 h after TI in the TI-induced animals under uncontrolled body temperature (UBT) compared to that under controlled body temperature (CBT) (about 37 °C). Neuroprotective effect was statistically significant when we used 5 and 10 mg/kg doses (p < 0.05, respectively). In the RIS-treated TI group, many CA1 pyramidal neurons of the hippocampus survived under UBT compared to those under CBT. In this group under UBT, post-treatment with RIS to TI-induced animals markedly attenuated the activation of glial cells, an increase of oxidative stress markers [dihydroethidium, 8-hydroxy-2' -deoxyguanosine (8-OHdG), and 4-Hydroxynonenal (4-HNE)], and a decrease of superoxide dismutase 2 (SOD2) in their CA1 pyramidal neurons. Furthermore, RIS-induced hypothermia was significantly interrupted by NBOH-2C-CN hydrochloride (a selective 5-HT_2A receptor agonist), but not bromocriptine mesylate (a D₂ receptor agonist). Our findings indicate that RIS-induced hypothermia can effectively protect neuronal cell death from TI injury through attenuation of glial activation and maintenance of antioxidants, showing that 5-HT_2A receptor is involved in RIS-induced hypothermia. Therefore, RIS could be introduced to reduce body temperature rapidly and might be applied to patients for hypothermic therapy following ischemic stroke.

Reproducible hindlimb ischemia model based on photochemically induced thrombosis to evaluate angiogenic effects

Critical limb ischemia is one of the most common types of peripheral arterial disease. Preclinical development of ischemia therapeutics relies on the availability of a relevant and reproducible in vivo disease model. Thus, establishing appropriate animal disease models is essential for the development of new therapeutic strategies. Currently, the most commonly employed model of hindlimb ischemia is the surgical induction method with ligation of the femoral artery and its branches after skin incision. However, the efficiency of the method is highly variable depending on the availability of skilled technicians. In addition, after surgical procedures, animals can quickly and spontaneously recover from damage, limiting observations of the therapeutic effect of potential agents. The aim of this study was to develop a hindlimb ischemia mouse model with similarities to human ischemic disease. To that end, a photochemical reaction was used to induce thrombosis in the hindlimb. After the photochemical reaction was induced by light irradiation, thrombotic plugs and adjacent red blood cell stasis were observed in hindlimb vessels in the light-irradiated zone. Additionally, the photochemically induced thrombosis maintained the ischemic condition and did not cause notable side effects in mice.

ANTIOXIDANT ENZYMES ACTIVITY IN EXPERIMENTAL ISCHEMIA-REPERFUSION INJURY

Background. Blood loss during civil and military limb trauma is the most common cause of preventable death. Complications due to the use of a hemostatic tourniquet are widely investigated nowadays. Therefore, the standards of the past have to be improved. Objective. The aim of the research is to study the reaction of the enzyme chain of the liver antioxidant system in the presence of modifications of ischemia-reperfusion injury (IRI). Methods. 210 white male-rats, aged 5-5.5 months, were used in the research. The dynamics of antioxidant enzymes activity catalase (Cat) and superoxide dismutase (SOD) in liver tissue in cases of modifications of ischemia-reperfusion injury (IRI) were studied. The period of investigation was in 24 hours, 3, 7, 14 days after the injury. Results. In cases of simulated IRI the catalase level mainly decreased at each period of the experiment. The peak of SOD activity was evidenced on the 1st, 3rd or 7th days after the experimental IRI according to the degree of trauma severity. Thus, IRI combined with severe blood loss and mechanical trauma caused the severest affection of the antioxidant system. Even a single application of hemostatic tourniquet caused similar wavelike reactions at different times. Conclusions. The development of IRI is accompanied by a significant depression of the liver antioxidant system. The most significant changes were evidenced in cases of IRI combined with blood loss and mechanical trauma, but even a single application of a tourniquet caused active response of the antioxidant enzymes.

Neuroinflammatory mechanisms of blood-brain barrier damage in ischemic stroke

As part of the neurovascular unit, the blood-brain barrier (BBB) is a unique, dynamic regulatory boundary that limits and regulates the exchange of molecules, ions, and cells between the blood and the central nervous system. Disruption of the BBB plays an important role in the development of neurological dysfunction in ischemic stroke. Blood-borne substances and cells have restricted access to the brain due to the presence of tight junctions between the endothelial cells of the BBB. Following stroke, there is loss of BBB tight junction integrity, leading to increased paracellular permeability, which results in vasogenic edema, hemorrhagic transformation, and increased mortality. Thus, understanding principal mediators and molecular mechanisms involved in BBB disruption is critical for the development of novel therapeutics to treat ischemic stroke. This review discusses the current knowledge of how neuroinflammation contributes to BBB damage in ischemic stroke. Specifically, we provide an updated overview of the role of cytokines, chemokines, oxidative and nitrosative stress, adhesion molecules, matrix metalloproteinases, and vascular endothelial growth factor as well as the role of different cell types in the regulation of BBB permeability in ischemic stroke.

Prophylactic Zinc and Therapeutic Selenium Administration Increases the Antioxidant Enzyme Activity in the Rat Temporoparietal Cortex and Improves Memory after a Transient Hypoxia-Ischemia

In the cerebral hypoxia-ischemia rat model, the prophylactic administration of zinc can cause either cytotoxicity or preconditioning effect, whereas the therapeutic administration of selenium decreases the ischemic damage. Herein, we aimed to explore whether supplementation of low doses of prophylactic zinc and therapeutic selenium could protect from a transient hypoxic-ischemic event. We administrated zinc (0.2 mg/kg of body weight; ip) daily for 14 days before a 10 min common carotid artery occlusion (CCAO). After CCAO, we administrated sodium selenite (6 μg/kg of body weight; ip) daily for 7 days. In the temporoparietal cerebral cortex, we determined nitrites by the Griess method and lipid peroxidation by the Gerard-Monnier assay. qPCR was used to measure mRNA of nitric oxide synthases, antioxidant enzymes, chemokines, and their receptors. We measured the enzymatic activity of SOD and GPx and protein levels of chemokines and their receptors by ELISA. We evaluated long-term memory using the Morris-Water maze test. Our results showed that prophylactic administration of zinc caused a preconditioning effect, decreasing nitrosative/oxidative stress and increasing GPx and SOD expression and activity, as well as eNOS expression. The therapeutic administration of selenium maintained this preconditioning effect up to the late phase of hypoxia-ischemia. Ccl2, Ccr2, Cxcl12, and Cxcr4 were upregulated, and long-term memory was improved. Pyknotic cells were decreased suggesting prevention of neuronal cell death. Our results show that the prophylactic zinc and therapeutic selenium administration induces effective neuroprotection in the early and late phases after CCAO.

Blood-brain barrier dysfunction in ischemic stroke: targeting tight junctions and transporters for vascular protection

The blood-brain barrier (BBB) is a physical and biochemical barrier that precisely controls cerebral homeostasis. It also plays a central role in the regulation of blood-to-brain flux of endogenous and exogenous xenobiotics and associated metabolites. This is accomplished by molecular characteristics of brain microvessel endothelial cells such as tight junction protein complexes and functional expression of influx and efflux transporters. One of the pathophysiological features of ischemic stroke is disruption of the BBB, which significantly contributes to development of brain injury and subsequent neurological impairment. Biochemical characteristics of BBB damage include decreased expression and altered organization of tight junction constituent proteins as well as modulation of functional expression of endogenous BBB transporters. Therefore, there is a critical need for development of novel therapeutic strategies that can protect against BBB dysfunction (i.e., vascular protection) in the setting of ischemic stroke. Such strategies include targeting tight junctions to ensure that they maintain their correct structure or targeting transporters to control flux of physiological substrates for protection of endothelial homeostasis. In this review, we will describe the pathophysiological mechanisms in cerebral microvascular endothelial cells that lead to BBB dysfunction following onset of stroke. Additionally, we will utilize this state-of-the-art knowledge to provide insights on novel pharmacological strategies that can be developed to confer BBB protection in the setting of ischemic stroke.

Crocin protects against cerebral- ischemia-induced damage in aged rats through maintaining the integrity of blood-brain barrier

BACKGROUND

A clear relationship exists between oxidative stress and disruption of blood-brain barrier (BBB) during cerebral ischemia, in which aging may exacerbate the extent of leakage. Here, we aim to examine the potential role of a water-soluble carotenoid-based antioxidant crocin on BBB damage in aged rats following cerebral ischemia.

METHODS

A two months oral administration of crocin was applied to 24-month-old rats followed by an induction of brain ischemia by middle cerebral artery occlusion (MCAO). Brain infarction volume, water content, and neurological behavior assessments were measured in these animals at 24 hours after MCAO as compared to vehicle-treated controls. Evans blue dye extravasation assay was used to evaluate the BBB integrity. The levels of tight junction proteins, oxidative stress, and MMP (matrix metalloproteinases) activities were also determined in the ipsilateral brains of the MCAO-treated rats.

RESULTS

MCAO-induced brain injury was alleviated by the pretreatment of crocin. Crocin-treated animals also showed the preserved BBB function in the presence of ischemic injury. The loss of tight junction proteins and enhanced NADPH oxidase in the ipsilateral brains of the MCAO-treated rats were both reduced by crocin. Finally, the induction of MMP-2 and MMP-9 by cerebral ischemia was partially blocked by crocin in aged rats.

CONCLUSION

These findings indicate that crocin or related antioxidants may protect against cerebral ischemia of elderly patients by maintaining the integrity of BBB in aged rats, an effect likely through repressing the activation of matrix metalloproteinase pathway.

Effect of ischemic preconditioning on antioxidant status in the gerbil hippocampal CA1 region after transient forebrain ischemia

Ischemic preconditioning (IPC) is a condition of sublethal transient global ischemia and exhibits neuroprotective effects against subsequent lethal ischemic insult. We, in this study, examined the neuroprotective effects of IPC and its effects on immunoreactive changes of antioxidant enzymes including superoxide dismutase (SOD) 1 and SOD2, catalase (CAT) and glutathione peroxidase (GPX) in the gerbil hippocampal CA1 region after transient forebrain ischemia. Pyramidal neurons of the stratum pyramidale (SP) in the hippocampal CA1 region of animals died 5 days after lethal transient ischemia without IPC (8.6% (ratio of remanent neurons) of the sham-operated group); however, IPC prevented the pyramidal neurons from subsequent lethal ischemic injury (92.3% (ratio of remanent neurons) of the sham-operated group). SOD1, SOD2, CAT and GPX immunoreactivities in the sham-operated animals were easily detected in pyramidal neurons in the stratum pyramidale (SP) of the hippocampal CA1 region, while all of these immunoreactivities were rarely detected in the stratum pyramidale at 5 days after lethal transient ischemia without IPC. Meanwhile, their immunoreactivities in the sham-operated animals with IPC were similar to (SOD1, SOD2 and CAT) or higher (GPX) than those in the sham-operated animals without IPC. Furthermore, their immunoreactivities in the stratum pyramidale of the ischemia-operated animals with IPC were steadily maintained after lethal ischemia/reperfusion. Results of western blot analysis for SOD1, SOD2, CAT and GPX were similar to immunohistochemical data. In conclusion, IPC maintained or increased the expression of antioxidant enzymes in the stratum pyramidale of the hippocampal CA1 region after subsequent lethal transient forebrain ischemia and IPC exhibited neuroprotective effects in the hippocampal CA1 region against transient forebrain ischemia.

Photothrombosis-induced Focal Ischemia as a Model of Spinal Cord Injury in Mice

Spinal cord injury (SCI) is a devastating clinical condition causing permanent changes in sensorimotor and autonomic functions of the spinal cord (SC) below the site of injury. The secondary ischemia that develops following the initial mechanical insult is a serious complication of the SCI and severely impairs the function and viability of surviving neuronal and non-neuronal cells in the SC. In addition, ischemia is also responsible for the growth of lesion during chronic phase of injury and interferes with the cellular repair and healing processes. Thus there is a need to develop a spinal cord ischemia model for studying the mechanisms of ischemia-induced pathology. Focal ischemia induced by photothrombosis (PT) is a minimally invasive and very well established procedure used to investigate the pathology of ischemia-induced cell death in the brain. Here, we describe the use of PT to induce an ischemic lesion in the spinal cord of mice. Following retro-orbital sinus injection of Rose Bengal, the posterior spinal vein and other capillaries on the dorsal surface of SC were irradiated with a green light resulting in the formation of a thrombus and thus ischemia in the affected region. Results from histology and immunochemistry studies show that PT-induced ischemia caused spinal cord infarction, loss of neurons and reactive gliosis. Using this technique a highly reproducible and relatively easy model of SCI in mice can be achieved that would serve the purpose of scientific investigations into the mechanisms of ischemia induced cell death as well as the efficacy of neuroprotective drugs. This model will also allow exploration of the pathological changes that occur following SCI in live mice like axonal degeneration and regeneration, neuronal and astrocytic Ca(2+) signaling using two-photon microscopy.

Methamphetamine effects on blood-brain barrier structure and function

Methamphetamine (Meth) is a widely abuse psychostimulant. Traditionally, studies have focused on the neurotoxic effects of Meth on monoaminergic neurotransmitter terminals. Recently, both in vitro and in vivo studies have investigated the effects of Meth on the BBB and found that Meth produces a decrease in BBB structural proteins and an increase in BBB permeability to various molecules. Moreover, preclinical studies are validated by clinical studies in which human Meth users have increased concentrations of toxins in the brain. Therefore, this review will focus on the structural and functional disruption of the BBB caused by Meth and the mechanisms that contribute to Meth-induced BBB disruption. The review will reveal that the mechanisms by which Meth damages dopamine and serotonin terminals are similar to the mechanisms by which the blood-brain barrier (BBB) is damaged. Furthermore, this review will cover the factors that are known to potentiate the effects of Meth (McCann et al., 1998) on the BBB, such as stress and HIV, both of which are co-morbid conditions associated with Meth abuse. Overall, the goal of this review is to demonstrate that the scope of damage produced by Meth goes beyond damage to monoaminergic neurotransmitter systems to include BBB disruption as well as provide a rationale for investigating therapeutics to treat Meth-induced BBB disruption. Since a breach of the BBB can have a multitude of consequences, therapies directed toward the treatment of BBB disruption may help to ameliorate the long-term neurodegeneration and cognitive deficits produced by Meth and possibly even Meth addiction.

Reduced brain edema and infarct volume in aquaporin-4 deficient mice after transient focal cerebral ischemia

Aquaporin-4 (AQP4) is a water channel expressed in astrocyte end-feet lining the blood-brain barrier. AQP4 deletion in mice is associated with improved outcomes in global cerebral ischemia produced by transient carotid artery occlusion, and focal cerebral ischemia produced by permanent middle cerebral artery occlusion (MCAO). Here, we investigated the consequences of 1-h transient MCAO produced by intraluminal suture blockade followed by 23 h of reperfusion. In nine AQP4(+/+) and nine AQP4(-/-) mice, infarct volume was significantly reduced by an average of 39 ± 4% at 24h in AQP4(-/-) mice, cerebral hemispheric edema was reduced by 23 ± 3%, and Evans Blue extravasation was reduced by 31 ± 2% (mean ± SEM). Diffusion-weighted magnetic resonance imaging showed greatest reduction in apparent diffusion coefficient around the occlusion site after reperfusion, with remarkably lesser reduction in AQP4(-/-) mice. The reduced infarct volume in AQP4(-/-) mice following transient MCAO supports the potential utility of therapeutic AQP4 inhibition in stroke.

Neuroprotection of antioxidant enzymes against transient global cerebral ischemia in gerbils

Experimentally transient global cerebral ischemia using animal models have been thoroughly studied and numerous reports suggest the involvement of oxidative stress in the pathogenesis of neuronal death in ischemic lesions. In animal models, during the reperfusion period after ischemia, increased oxygen supply results in the overproduction of reactive oxygen species (ROS), which are involved in the process of cell death. ROS, such as superoxide anions, hydroxyl free radicals, hydrogen peroxide and nitric oxide are produced as a consequence of metabolic reactions and central nervous system activity. These reactive species are directly involved in the oxidative damage of cellular macromolecules such as nucleic acids, lipids and proteins in ischemic tissues, which can lead to cell death. Antioxidant enzymes are believed to be among the major mechanisms by which cells counteract the deleterious effect of ROS after cerebral ischemia. Consequently, antioxidant strategies have been long suggested as a therapy for experimental ischemic stroke; however, clinical trials have not yet been able to promote the translation of this concept into patient treatment regimens. This article focuses on the contribution of oxidative stress or antioxidants to the post-ischemic neuronal death following transient global cerebral ischemia by using a gerbil model.

Atorvastatin protects against cerebral ischemia/reperfusion injury through anti-inflammatory and antioxidant effects

In addition to its lipid-lowering effect, atorvastatin exerts anti-inflammatory and antioxidant effects as well. In this study, we hypothesized that atorvastatin could protect against cerebral ischemia/reperfusion injury. The middle cerebral artery ischemia/reperfusion model was established, and atorvastatin, 6.5 mg/kg, was administered by gavage. We found that, after cerebral ischemia/reperfusion injury, levels of the inflammation-related factors E-selectin and myeloperoxidase were upregulated, the oxidative stress-related marker malondialdehyde was increased, and superoxide dismutase activity was decreased in the ischemic cerebral cortex. Atorvastatin pretreatment significantly inhibited these changes. Our findings indicate that atorvastatin protects against cerebral ischemia/reperfusion injury through anti-inflammatory and antioxidant effects.

Astrocytic modulation of blood brain barrier: perspectives on Parkinson's disease

The blood–brain barrier (BBB) is a tightly regulated interface in the Central Nervous System (CNS) that regulates the exchange of molecules in and out from the brain thus maintaining the CNS homeostasis. It is mainly composed of endothelial cells (ECs), pericytes and astrocytes that create a neurovascular unit (NVU) with the adjacent neurons. Astrocytes are essential for the formation and maintenance of the BBB by providing secreted factors that lead to the adequate association between the cells of the BBB and the formation of strong tight junctions. Under neurological disorders, such as chronic cerebral ischemia, brain trauma, Epilepsy, Alzheimer and Parkinson’s Diseases, a disruption of the BBB takes place, involving a lost in the permeability of the barrier and phenotypical changes in both the ECs and astrocytes. In this aspect, it has been established that the process of reactive gliosis is a common feature of astrocytes during BBB disruption, which has a detrimental effect on the barrier function and a subsequent damage in neuronal survival. In this review we discuss the implications of astrocyte functions in the protection of the BBB, and in the development of Parkinson’s disease (PD) and related disorders. Additionally, we highlight the current and future strategies in astrocyte protection aimed at the development of restorative therapies for the BBB in pathological conditions.

Neuroprotection of posttreatment with risperidone, an atypical antipsychotic drug, in rat and gerbil models of ischemic stroke and the maintenance of antioxidants in a gerbil model of ischemic stroke

Risperidone, an atypical antipsychotic drug, has been discovered to have some beneficial effects beyond its original effectiveness. The present study examines the neuroprotective effects of risperidone against ischemic damage in the rat and gerbil induced by transient focal and global cerebral ischemia, respectively. The results showed that pre- and posttreatment with 4 mg/kg risperidone significantly protected against neuronal death from ischemic injury. Many NeuN-immunoreactive neurons and a few F-J B-positive cells were found in the rat cerebral cortex and gerbil hippocampal CA1 region (CA1) in the risperidone-treated ischemia groups compared with those in the vehicle-treated ischemia group. In addition, treatment with risperidone markedly attenuated the activation of microglia in the gerbil CA1. On the other hand, we found that treatment with risperidone significantly maintained the antioxidants levels in the ischemic gerbil CA1. Immunoreactivities of superoxide dismutases 1 and 2, catalase, and glutathione peroxidase were maintained in the stratum pyramidale of the CA1; the antioxidants were very different from those in the vehicle-treated ischemia groups. In brief, our present findings indicate that posttreatment as well as pretreatment with risperidone can protect neurons in the rat cerebral cortex and gerbils CA1 from transient cerebral ischemic injury and that the neuroprotective effect of risperidone may be related to attenuation of microglial activation as well as maintenance of antioxidants.

Cerebroprotective effects of red ginseng extract pretreatment against ischemia-induced oxidative stress and apoptosis

Panax ginseng C.A. Meyer has been traditionally used as a medicinal plant and has beneficial effects due to pharmacological properties. Although ginseng is thought to be protective under abnormal conditions, the effects of pretreatment with red ginseng (RG) extract on ischemic stroke have not been fully elucidated. We investigated the protective effects of RG extract after focal cerebral ischemia in mice. Crude RG extract (360 mg/kg) was administered intraperitoneally for 2 weeks. Mice were then subjected to occlusion of the middle cerebral artery for 1 hour, followed by reperfusion for 4 and 24 hours. Pretreatment with RG extract followed by ischemia/reperfusion (I/R) resulted in significant reduction of oxidized hydroethidine signals in ischemic areas. At 4 and 24 hours after I/R, the number of 8-hydroxyguanosine and apoptosis signal-regulating kinase 1 (ASK1)-positive cells decreased in the ischemic penumbra as seen using immunofluorescent staining. Western blotting showed that RG efficiently attenuated the protein levels of activated ASK1 in the ischemic penumbra. Consequently, DNA fragmentation and the infarct volume were reduced by RG extract pretreatment 24 hours after I/R. Also, RG extract resulted in better performance in rotarod test after I/R. Thus, RG pretreatment demonstrates a protective effect at suppressing ischemia-induced oxidative stress and apoptosis in ischemic lesions. Pretreatment with crude RG extract may be an effective strategy for preventing brain injury after an ischemic stroke.

Neuroprotective effects of Alpinia katsumadai against experimental ischemic damage via control of oxidative stress

CONTEXT

Alpinia katsumadai (Zingiberaceae) has been identified by the National Plant Quarantine Service in Korea. The extract of Alpinia katsumadai seed (EAKS) has antioxidant activities.

OBJECTIVE

We investigated the neuroprotective effects of EAKS on ischemic damage in the gerbil hippocampal CA1 region after transient cerebral ischemia.

MATERIALS AND METHODS

The ethanol extract of EAKS was obtained by organic solvent, collected in Kangwon province (South Korea) and orally administered using a feeding needle once a day for one week before transient cerebral ischemia in gerbils.

RESULT

We adapted oral administration of 25 and 50 mg/kg EAKS because there are no data about the absorption and metabolism of EKAS. We found a significant neuroprotection in the 50 mg/kg EAKS-treated ischemia group, not in the 25 mg/kg EAKS-treated ischemia group, at 4 days ischemia-reperfusion (I-R). In the 50 mg/kg EAKS-treated ischemia group, about 68% of pyramidal neurons in the CA1 region were immunostained with neuronal nuclei (NeuN) 4 days after I-R, compared to the vehicle-treated ischemia group. 8-Hydroxy-2'-deoxyguanosine (a marker for DNA damage) and 4-hydroxy-2-nonenal (a marker for lipid peroxidation) immunoreactivity in the CA1 region of the EAKS-treated ischemia group were not markedly changed compared to the vehicle-treated ischemia group. In addition, Cu,Zn- and Mn-SOD immunoreactivity in the CA1 region of the EAKS-treated ischemia group were increased compared to the vehicle-treated ischemia group.

DISCUSSION

Repeated supplements of EAKS could protect neurons against ischemic damage, showing that DNA damage and lipid peroxidation are attenuated and SODs are increased in the ischemic CA1 region.

Blood-brain barrier integrity and glial support: mechanisms that can be targeted for novel therapeutic approaches in stroke

The blood-brain barrier (BBB) is a critical regulator of brain homeostasis. Additionally, the BBB is the most significant obstacle to effective CNS drug delivery. It possesses specific charcteristics (i.e., tight junction protein complexes, influx and efflux transporters) that control permeation of circulating solutes including therapeutic agents. In order to form this "barrier," brain microvascular endothelial cells require support of adjacent astrocytes and microglia. This intricate relationship also occurs between endothelial cells and other cell types and structures of the CNS (i.e., pericytes, neurons, extracellular matrix), which implies existence of a "neurovascular unit." Ischemic stroke can disrupt the neurovascular unit at both the structural and functional level, which leads to an increase in leak across the BBB. Recent studies have identified several pathophysiological mechanisms (i.e., oxidative stress, activation of cytokine-mediated intracellular signaling systems) that mediate changes in the neurovascular unit during ischemic stroke. This review summarizes current knowledge in this area and emphasizes pathways (i.e., oxidative stress, cytokine-mediated intracellular signaling, glial-expressed receptors/targets) that can be manipulated pharmacologically for i) preservation of BBB and glial integrity during ischemic stroke and ii) control of drug permeation and/or transport across the BBB. Targeting these pathways present a novel opportunity for optimization of CNS delivery of therapeutics in the setting of ischemic stroke.

Vascular and neuronal ischemic damage in cryonics patients

Cryonics technology seeks to cryopreserve the anatomical basis of the mind so that future medicine can restore legally dead cryonics patients to life, youth, and health. Most cryonics patients experience varying degrees of ischemia and reperfusion injury. Neurons can survive ischemia and reperfusion injury more than is generally believed, but blood vessels are more vulnerable, and such injury can impair perfusion of vitrifying cryoprotectant solution intended to eliminate ice formation in the brain. Forms of vascular and neuronal damage are reviewed, along with means of mitigating that damage. Recommendations are also made for preventing such damage.

NADPH oxidases as therapeutic targets in ischemic stroke

Reactive oxygen species (ROS) act physiologically as signaling molecules. In pathological conditions, such as ischemic stroke, ROS are released in excessive amounts and upon reperfusion exceed the body's antioxidant detoxifying capacity. This process leads to brain tissue damage during reoxygenation. Consequently, antioxidant strategies have long been suggested as a therapy for experimental stroke, but clinical trials have not yet been able to promote the translation of this concept into patient treatment regimens. As an evolution of this concept, recent studies have targeted the sources of ROS generation-rather than ROS themselves. In this context, NADPH oxidases have been identified as important generators of ROS in the cerebral vasculature under both physiological conditions in general and during ischemia/reoxygenation in particular. Inhibition of NADPH oxidases or genetic deletion of certain NADPH oxidase isoforms has been found to considerably reduce ischemic injury in experimental stroke. This review focuses on recent advances in the understanding of NADPH oxidase-mediated tissue injury in the cerebral vasculature, particularly at the level of the blood-brain barrier, and highlights promising inhibitory strategies that target the NADPH oxidases.

The neurovascular unit and combination treatment strategies for stroke

Tissue plasminogen activator (tPA) administered within 4.5h of symptom onset restores cerebral blood flow (CBF) and promotes neurological recovery of stroke patients. However, the narrow therapeutic time window and the risk of intracerebral hemorrhage after tPA treatment pose major hurdles to its clinical usage. In light of the failures of neuroprotective therapies in clinical trials, emerging concepts suggest that neuroprotection alone without restoration of tissue perfusion and vascular integrity may not be adequate for treatment of acute stroke. Here we review evidence of the use of adjuvant pharmacological agents to extend the therapeutic window for tPA via targeting the neurovascular unit and the underlying mechanisms of the combination therapy in experimental stroke.

Ferulic Acid Reduces Cerebral Infarct Through Its Antioxidative and Anti-Inflammatory Effects Following Transient Focal Cerebral Ischemia in Rats

Both Angelica sinensis (Oliv.) Diels (AS) and Ligusticum chuanxiong Hort. (LC) have been used to treat stroke in traditional Chinese medicine for centuries. Ferulic acid (FA), a component in both AS and LC, plays a role in neuroprotection. The purpose of this study was to investigate the effects of FA on cerebral infarct and the involvement of neuroprotective pathway. Rats underwent 2 hours and 24 hours of reperfusion after 90 min middle cerebral artery occlusion (MCAo). The cerebral infarct and neurological deficits were measured after 24 hours of reperfusion. Furthermore, the expression of superoxide radicals, intercellular adhesion molecule-1 (ICAM-1), myeloperoxidase (MPO), nuclear factor-κB (NF-κB) immunoreactive cells were assessed after 2 hours and 24 hours of reperfusion. Administration of 80 and 100 mg/kg of FA at the beginning of MCAo significantly reduced cerebral infarct and neurological deficit-score, similar results were obtained by 100 mg/kg of FA administered 30 min after MCAo. FA treatment (100 mg/kg i.v.) effectively suppressed superoxide radicals in the parenchyma lesion, and ICAM-1 immunoreactive vessels in the ischemic striatum after 2 hours of reperfusion. FA (100 mg/kg i.v.) reduced the expression of ICAM-1 and NF-κB in the ischemic cortex and striatum, also down-regulated MPO immunoreactive cells in the ischemic cortex after 24 hours of reperfusion. These results showed that the effect of FA on reducing cerebral infarct area and neurological deficit-score were at least partially attributed to the inhibition of superoxide radicals, ICAM-1 and NF-κB expression in transient MCAo rats.

Increases of antioxidants are related to more delayed neuronal death in the hippocampal CA1 region of the young gerbil induced by transient cerebral ischemia

In age-related studies, young animals are resistant to ischemic damage. In present study, we investigated the neuronal death of pyramidal neurons and compared changes in the immunoreactivities and levels of antioxidants, Cu/Zn-SOD (SOD1), Mn-SOD (SOD2), catalase (CAT) and glutathione peroxidase (Gpx), in the hippocampal CA1 region between adult and young gerbils after 5 min of transient cerebral ischemia. In the adult ischemia-group, only a few (12%) of CA1 pyramidal neurons survived 4 days after ischemia-reperfusion (I-R); however, in the 4 days after I-R the young group, most of CA1 pyramidal neurons survived. Seven days after I-R, many (about 39%) of CA1 pyramidal neurons survived, thereafter, the neuronal death in the CA1 pyramidal neurons was not significantly changed. The immunoreactivities of all the antioxidants were well detected in CA1 pyramidal neurons in the adult sham-groups; in the young sham-groups, they were distinctively low compared to those in the adult sham-group. Four days after I-R in the adult group, all the immunoreactivities in the pyramidal neurons were dramatically deceased. However, at this time after I-R in the young groups, they were dramatically increased in the pyramidal neurons. From 7 days after I-R, all the immunoreactivities in the pyramidal neurons in the young ischemia-groups were distinctively decreased. In addition, the levels of all the antioxidants in the CA1 region of the young sham-groups were lower than those in the adult sham-group. Four days after I-R in the adult groups, the levels of all the antioxidants were dramatically deceased; however, at this time in the young ischemia-groups, they were distinctively increased in the CA1 region. Seven days after I-R, all the antioxidants levels in the CA1 region were distinctively decreased. In brief, we conclude that the increased antioxidants levels were related to a less and much delayed neuronal death in the CA1 pyramidal neurons in the young group following I-R injury.

Iron mediates endothelial cell damage and blood-brain barrier opening in the hippocampus after transient forebrain ischemia in rats

Blood cells are transported into the brain and are thought to participate in neurodegenerative processes following hypoxic ischemic injury. We examined the possibility that transient forebrain ischemia (TFI) causes the blood-brain barrier (BBB) to become permeable to blood cells, possibly via dysfunction and degeneration of endothelial cells in rats. Extravasation of Evans blue and immunoglobulin G (IgG) was observed in the hippocampal CA1-2 areas within 8 h after TFI, and peaked at 48 h. This extravasation was accompanied by loss of tight junction proteins, occludin, and zonula occludens-1, and degeneration of endothelial cells in the CA1-2 areas. Iron overload and mitochondrial free radical production were evident in the microvessel endothelium of the hippocampus before endothelial cell damage occurred. Administration of deferoxamine (DFO), an iron chelator, or Neu2000, an antioxidant, blocked free radical production and endothelial cell degeneration. Our findings suggest that iron overload and iron-mediated free radical production cause loss of tight junction proteins and degeneration of endothelial cells, opening of the BBB after TFI.

Disturbance of perineuronal nets in the perilesional area after photothrombosis is not associated with neuronal death

Perineuronal nets (PNNs) are a condensed form of extracellular matrix that covers the surface of a subset of neurons. Their presence limits neuronal plasticity and may protect neurons against harmful agents. Here we analyzed the relationship between spatiotemporal changes in PNN expression and cell death markers after focal cortical photothrombotic stroke in rats. We registered a substantial decrease in PNN density using Wisteria floribunda agglutinin staining and CAT-315 and brevican immunoreactivity; the decrease occurred not only in the lesion core but also in the perilesional and remote cortex as well as in homotopic contralateral cortical regions. Fluoro Jade C and TUNEL staining in perilesional and remote areas, however, showed a low density of dying cells. Our results suggest that the PNN reduction was not a result of cellular death and could be considered an attempt to create conditions favorable for synaptic remodeling.

Vascular Dysfunction in Brain Hemorrhage: Translational Pathways to Developing New Treatments from Old Targets

Hemorrhagic stroke which is a form of stroke that affects 20% of all stroke patients is a devastating condition for which new treatments must be developed. Current treatment methods are quite insufficient to reduce long term morbidity and high mortality rate, up to 50%, associated with bleeding into critical brain structures, into ventricular spaces and within the subarachnoid space. During the last 10-15 years, significant advances in the understanding of important mechanisms that contribute to cell death and clinical deficits have been made. The most important observations revolve around a key set of basic mechanisms that are altered in brain bleeding models, including activation of membrane metalloproteinases, oxidative stress and both inflammatory and coagulation pathways. Moreover, it is now becoming apparent that brain hemorrhage can activate the ischemic stroke cascade in neurons, glial cells and the vascular compartment. The activation of multiple pathways allows comes the opportunity to intervene pharmacologically using monotherapy or combination therapy. Ultimately, combination therapy or pleiotropic compounds with multi-target activities should prove to be more efficacious than any single therapy alone. This article provides a comprehensive look at possible targets for small molecule intervention as well as some new approaches that result in metabolic down-regulation or inhibition of multiple pathways simultaneously.

Decisive role of apurinic/apyrimidinic endonuclease/Ref-1 in initiation of cell death

The apurinic/apyrimidinic endonuclease/redox effector factor-1 (APE/Ref-1) is involved in the base excision repair of apurinic/apyrimidinic sites induced by oxidative DNA damage. APE/Ref-1 was decreased by kainic acid (KA) injury in a time-dependent manner at the level of proteins, not transcripts. We investigated whether alteration of APE/Ref-1 amounts would influence hippocampal cell fate, survival or death, after KA injury. Overexpression of APE/Ref-1 using adenovirus and restoration of APE small peptides significantly reduced KA-induced hippocampal cell death. Both silencing of APE/Ref-1 by siRNA and inhibition of endonuclease by an antibody significantly increased caspase-3 activity and apoptotic cell death triggered from the early time after exposure to KA. These findings suggest that cell death is initiated by reducing APE/Ref-1 protein and inhibiting its repair function in spite of enough protein amounts. In conclusion, APE/Ref-1 may be a regulator of cell death initiation, and APE small peptides could provide molecular mechanism-based therapies for neuroprotection in progressive excitotoxic neuronal damage.

Kinetics differ between copper-zinc and manganese superoxide dismutase activity with acute ischemic stroke

This study aimed to clarify the kinetics of copper-zinc (CuZn) and manganese (Mn) superoxide dismutase (SOD) activity in acute ischemic stroke victims. Using the nitrite method, we investigated sequential changes in CuZn and Mn SOD activity in the cerebrospinal fluid (CSF) of 8 patients with acute ischemic stroke. SOD activity in each patient was measured at 36 hours and 3, 7, 14, and 28 days after stroke. CuZn SOD activity in CSF peaked 3 days after stroke, with values gradually decreasing after 7 days. In contrast, Mn SOD activity remained significantly lower in the stroke group than in controls throughout the study. These findings may reflect differences between the 2 isoenzymes in terms of the distribution, role, and method of synthesis in brain tissue.

Hydroethidine- and MitoSOX-derived red fluorescence is not a reliable indicator of intracellular superoxide formation: another inconvenient truth

Hydroethidine (HE; or dihydroethidium) is the most popular fluorogenic probe used for detecting intracellular superoxide radical anion. The reaction between superoxide and HE generates a highly specific red fluorescent product, 2-hydroxyethidium (2-OH-E(+)). In biological systems, another red fluorescent product, ethidium, is also formed, usually at a much higher concentration than 2-OH-E(+). In this article, we review the methods to selectively detect the superoxide-specific product (2-OH-E(+)) and the factors affecting its levels in cellular and biological systems. The most important conclusion of this review is that it is nearly impossible to assess the intracellular levels of the superoxide-specific product, 2-OH-E(+), using confocal microscopy or other fluorescence-based microscopic assays and that it is essential to measure by HPLC the intracellular HE and other oxidation products of HE, in addition to 2-OH-E(+), to fully understand the origin of red fluorescence. The chemical reactivity of mitochondria-targeted hydroethidine (Mito-HE, MitoSOX red) with superoxide is similar to the reactivity of HE with superoxide, and therefore, all of the limitations attributed to the HE assay are applicable to Mito-HE (or MitoSOX) as well.

Agrin, aquaporin-4, and astrocyte polarity as an important feature of the blood-brain barrier

The blood-brain barrier (BBB) does not exclusively refer to brain endothelial cells, which are the site of the barrier proper. In the past few years, it has become increasingly clear that BBB endothelial cells depend considerably on the brain microenvironment to a degree exceeding the environmental influence in other organs. The concept of the BBB has been continuously developed over the decades, culminating now in the recognition that endothelial cell function in the brain is not limited to simply mediating energy and oxygen transfer between blood and neural tissue. Endothelial cells are rather "Janus-headed beings" that are active partners of both luminal molecules and cells, as well as subendothelial cells such as pericytes, astrocytes, and neurons. In this overview, the authors present and discuss both the role of astroglial cells in managing the BBB and aspects of pathological alterations in the brain as far as the BBB is involved. After a brief introduction of the BBB that describes the structure and function of the brain capillary endothelial cells, the authors report on both the water channel protein aquaporin-4 (AQP4) in astrocytes and the extracellular matrix between astrocytes/pericytes and endothelial cells. The AQP4 has an important impact on the homeostasis in the brain parenchyma; however, the mechanistic cascade from the composition of the astrocyte membrane to the maintenance of BBB properties in the endothelial cells, including their tight junction formation, is still completely unknown.

Oral administration of grape polyphenol extract ameliorates cerebral ischemia/reperfusion-induced neuronal damage and behavioral deficits in gerbils: comparison of pre- and post-ischemic administration

Oxidative stress has been regarded as an important underlying cause for the delayed neuronal death (DND) after cerebral ischemia. In this study, the effects of short-term oral administration of grape polyphenol extract (GPE) on ischemia/reperfusion (I/R) injury in a gerbil global ischemia model were determined. Ischemia was induced by occlusion of the common carotid arteries for 5 min. GPE (30 mg/ml)-containing formula or formula without GPE was administered daily via gavage for 4 days prior to and/or for 4 days after I/R. I/R resulted in hyperlocomotion, extensive DND, oxidative and fragmented DNA damage, and an increase in reactive astrocytes and microglial cells in the hippocampal CA1 region. GPE administration for 4 days prior to I/R and for 4 days after I/R attenuated DND, DNA damage and glial cell activation. However, neuroprotection was more pronounced when GPE was administered for 4 days after I/R than when administered for 4 days prior to I/R. GPE administration after I/R attenuated I/R-induced hyperlocomotion. These findings indicate that oral GPE intake may confer protection against I/R injury and emphasize that early intervention may be an effective therapeutic measure for ameliorating brain injury in stroke.

The development of an improved preclinical mouse model of intracerebral hemorrhage using double infusion of autologous whole blood

The present study was conducted in mice to validate a double blood infusion model of intracerebral hemorrhage (ICH) that does not use anticoagulant. We investigated the effect of intrastriatal infusion of blood on hematoma volume, neurologic function, brain edema and swelling, and markers of neuroinflammation and oxidative DNA damage. Anesthetized C57BL/6 adult male mice were infused in the left striatum with 4 microl of blood over 20 min at 0.2 microl /min; the needle was left in place for 7 min, and the remaining 6 microl of blood was then infused over 30 min. The injection needle was slowly withdrawn 20 min after the second injection. Sham-operated control mice received only needle insertion. The hematoma produced in this model was primarily restricted to the striatum, and the mice demonstrated severe neurologic deficits that appeared within 60 min and remained evident at 72 h. Brain water content and swelling were significantly increased and were associated with a marked increase in ICH-induced neutrophil infiltration, microglial/macrophage and astrocyte activation, cytochrome c release, and oxidative DNA damage. Other groups have mixed the anticoagulant heparin with the infused blood, an agent that could affect in vivo clot formation. We believe that this double blood infusion model that does not use anticoagulant improves upon the procedure and provides an easy and reproducible alternative for inducing ICH in mice; it should be useful for studying the pathophysiology of ICH and for testing potential pharmaceutical and surgical interventions.