Brain Cell Injury Research Articles

Homocysteine Aggravates Cortical Neural Cell Injury through Neuronal Autophagy Overactivation following Rat Cerebral Ischemia-Reperfusion.

Elevated homocysteine (Hcy) levels have been reported to be involved in neurotoxicity after ischemic stroke. However, the underlying mechanisms remain incompletely understood to date. In the current study, we hypothesized that neuronal autophagy activation may be involved in the toxic effect of Hcy on cortical neurons following cerebral ischemia. Brain cell injury was determined by hematoxylin-eosin (HE) staining and TdT-mediated dUTP Nick-End Labeling (TUNEL) staining. The level and localization of autophagy were detected by transmission electron microscopy, western blot and immunofluorescence double labeling. The oxidative DNA damage was revealed by immunofluorescence of 8-Hydroxy-2′-deoxyguanosine (8-OHdG). Hcy treatment aggravated neuronal cell death, significantly increased the formation of autophagosomes and the expression of LC3B and Beclin-1 in the brain cortex after middle cerebral artery occlusion-reperfusion (MCAO). Immunofluorescence analysis of LC3B and Beclin-1 distribution indicated that their expression occurred mainly in neurons (NeuN-positive) and hardly in astrocytes (GFAP-positive). 8-OHdG expression was also increased in the ischemic cortex of Hcy-treated animals. Conversely, LC3B and Beclin-1 overexpression and autophagosome accumulation caused by Hcy were partially blocked by the autophagy inhibitor 3-methyladenine (3-MA). Hcy administration enhanced neuronal autophagy, which contributes to cell death following cerebral ischemia. The oxidative damage-mediated autophagy may be a molecular mechanism underlying neuronal cell toxicity of elevated Hcy level.

Abstract P161: Angiotensin Receptor Blockade Decreases Glutamate-induced Brain Inflammation

Chronic Kidney Disease (CKD) is very frequently associated with brain inflammation and cell injury leading to cognitive loss. At present a combined treatment of related kidney and brain injury has never been proposed. We focused on glutamate-induced excitotoxicity and neuronal inflammation, and on the effects of candesartan, a renoprotective Angiotensin Receptor Blocker (ARB) ameliorating hypertension and diabetes-induced kidney damage, and with accompanying neuroprotective efficacy. Primary cerebellar granule cells (CGC) were exposed to 100 μM glutamate and pre-treated for one hour with candesartan at neuroprotective concentrations (10 μM). Gene expression was quantified by qPCR. Candesartan significantly reduced glutamate-induced inflammation. Multiple group comparisons were performed by one-way ANOVA followed by Newman-Keuls post-test. Exposure to glutamate significantly reduced neuronal viability while up-regulating the expression of multiple genes on pro-inflammatory pathways, including Toll-like receptor 7 (Tlr7) and Nuclear factor of kappa light polypeptide gene enhancer in B-cells 2, p49/p100 (Nfkpb2). * p<0.01, ** p< 0.05, vs control; # p< 0.01 vs glutamate. In all cases, pretreatment with candesartan completely prevented glutamate-induced neurotoxicity. Our results indicate that Angiotensin II receptor blockade with candesartan is strongly and directly neuroprotective, significantly ameliorating neuronal injury as a result of glutamate excitotoxicity. These results support the use of candesartan and other ARBs for the concomitant treatment of CKD and associated neuronal injury.

Brain cell injury in HIV infection: when does it start and can it be stopped?

The study by Young and colleagues1 in this issue of Neurology® used a technique called magnetic resonance spectroscopy (MRS) to examine the brain chemistry of patients with HIV. MRS is a noninvasive method of measuring the levels of certain chemicals, or “metabolites,” in the brain. One metabolite, N -acetylaspartate (NAA), is a marker of healthy brain cells. Three other metabolites, choline (Cho), myo-inositol (MI), and glutamate (Glu), are markers of damaged brain cells and inflammation (see table).

Radioprotective effects of valproic acid, a histone deacetylase inhibitor, in the rat brain.

Radiotherapy is commonly used in the treatment of brain tumors but can cause significant damage to surrounding normal brain. The radioprotective effects of valproic acid (VPA) on normal tissue in the rat brain were evaluated following irradiation. Male Wistar rats were used in the present study and 48 rats were randomly divided into four groups consisting of 12 rats each. The whole-brain irradiation (WBI) was delivered by X-ray and the rats received the following treatment once a day for 5 days. The control group (sham-exposed group) received sham irradiation plus physiological saline. The VPA group received sham irradiation plus 150 mg VPA/kg. The X-ray group received WBI plus physiological saline. The combined group received WBI plus 150 mg/kg intraperitoneally VPA. A total of 6 months post-irradiation, the rats were sacrificed and the brains were harvested. Cell apoptosis in the cortex was determined by immunohistochemistry 24 h post-irradiation using an antibody for protein caspase-3. Transmission electron microscope (TEM) analyses were used to assess the effects of VPA on the radioprotection of rat normal brain cells 6 months post-irradiation. The weights of the animals in the TEM group measured over the two weeks after the first injection of VPA were also observed. Histological findings demonstrated that apoptosis occurred on the cortex 1 day after treatment, peaking in the X-ray group. The cells of the combined group showed a moderate caspase-3 staining compared to the X-ray group. There was a trend towards a lower body weight of the X-ray group following irradiation compared to either no-irradiation or rats of the combined group, although there was no significant difference in the average weight between the combined group and irradiated rats. Mild swelling of the capillary endothelial cells in the irregular lumen was observed in the combined group, whereas the X-ray group showed a severe structural disorder. In conclusion, VPA supplementation during radiotherapy may be beneficial for radioprotection following WBI by reducing normal brain cell injury.

Systemic inflammation induces a profound long term brain cell injury in rats.

The long term impact of neuroflammation induced by systemic inflammation on astroglial transcription factor nuclear factor (NF)-kappaB activation in the sub-region of hippocampus as well as its' association with the ultra-structural changes in brain cells are yet unknow. In this study, rats received 10 mg/kg of lipopolysaccharide (LPS, ip injection) and NF-kappaBp65 expression on the astroglia as well as the neuronal and astroglial ultra-structural changes and/or death and microvasculature damage were assessed with immunofluorescence and transmission electron microscopy respectively up to 16 days after treatment. The results showed that in the CA1 and CA3 region of the hippocampus, the fluorescence intensity of NF-kappaBp65 was increased from day 1 after LPS injection, reaching a peak at day 3, and stayed at higher level when compared to the control up to 16 days after LPS treatment (P<0.05). Electron microscopy studies revealed sustainable substructural alterations, injury or even death of astrocytes, neurons and capillaries even after 16 days post LPS injection. Our study demonstrated that long-term sustainable activation of astroglial NF-kappaB following systemic inflammation was associated with brain cell and microvasculature injury in the sub-region of the hippocampus which ultimately likely results in brain functional impairment.

Endotoxin-induced lung alveolar cell injury causes brain cell damage.

Sepsis is the most common cause of acute respiratory distress syndrome, a severe lung inflammatory disorder with an elevated morbidity and mortality. Sepsis and acute respiratory distress syndrome involve the release of inflammatory mediators to the systemic circulation, propagating the cellular and molecular response and affecting distal organs, including the brain. Since it has been reported that sepsis and acute respiratory distress syndrome contribute to brain dysfunction, we investigated the brain-lung crosstalk using a combined experimental invitro airway epithelial and brain cell injury model. Conditioned medium collected from an invitro lipopolysaccharide-induced airway epithelial cell injury model using human A549 alveolar cells was subsequently added at increasing concentrations (no conditioned, 2%, 5%, 10%, 15%, 25%, and 50%) to a rat mixed brain cell culture containing both astrocytes and neurons. Samples from culture media and cells from mixed brain cultures were collected before treatment, and at 6 and 24 h for analysis. Conditioned medium at 15% significantly increased apoptosis in brain cell cultures 24 h after treatment, whereas 25% and 50% significantly increased both necrosis and apoptosis. Levels of brain damage markers S100 calcium binding protein B and neuron-specific enolase, interleukin-6, macrophage inflammatory protein-2, as well as matrix metalloproteinase-9 increased significantly after treating brain cells with ≥2% conditioned medium. Our findings demonstrated that human epithelial pulmonary cells stimulated with bacterial lipopolysaccharide release inflammatory mediators that are able to induce a translational clinically relevant and harmful response in brain cells. These results support a brain-lung crosstalk during sepsis and sepsis-induced acute respiratory distress syndrome.

Brain cell injury following cerebral ischemia and reperfusion: positive effects of ICAM-1/ neuroprotective role of Taurine

Brain cell injury following cerebral ischemia and reperfusion: positive effects of ICAM-1/ neuroprotective role of Taurine

FEATURES

Is Aging a Risk Factor for Cancer? Adverse Effects of Substance Abuse on Aging: Implication of Brain Cell Injury Diabetes and the Elderly The Necessity for Early Therapeutic Interventions in Dementia: The Role of Neurosteroids

Meloxicam attenuates brain cell injury following cerebral ischemia and reperfusion via down regulation of proinflammatory response

Meloxicam attenuates brain cell injury following cerebral ischemia and reperfusion via down regulation of proinflammatory response

Is therapeutic hypothermia immunosuppressive?

Is therapeutic hypothermia immunosuppressive?

7A45 脳細胞損傷によるCa^&lt;2+&gt;増加を再現する脳物理モデルの構築(OS02 傷害バイオメカニクス2)

7A45 脳細胞損傷によるCa^&lt;2+&gt;増加を再現する脳物理モデルの構築(OS02 傷害バイオメカニクス2)

Effects of fluctuating glucose concentrations on oxidative metabolism of glucose in cultured neurons and astroglia

The objective of the present study was to evaluate the effects of hyperglycemia on glucose metabolism of brain cells. Not only a sustained hyperglycemic state, but also a fluctuating plasma glucose concentration has been implicated in the pathogenesis of diabetic angiopathy. Acutely increasing plasma glucose levels have not been reported to alter glucose utilization of the brain as a whole. In the present study, we examined the effects of chronic (3 weeks) or short-term (24-hour) exposure to a high glucose concentration on the oxidative metabolism of neurons and astroglia. Cells were prepared from Sprague-Dawley rats and cultured in the presence of a high (22 mM) or low (5 mM) concentration of glucose. The high or low glucose media did not alter either the rates of [14C]deoxyglucose phosphorylation (an indicator of total glucose utilization) or [14C]lactate and [14C]pyruvate oxidation (indicators of oxidative glucose metabolism) in neurons. In contrast, chronic or short-term exposure to a high glucose concentration resulted in significant decreases in oxidation of [14C]acetate, an astrocyte-specific reporter molecule, or [14C]lactate and [14C]pyruvate oxidation in the astroglia. Thus, either chronic or short-term increases in the glucose concentration suppressed oxidative metabolism only in astroglia, indicating neuro-protective roles against hyperglycemic brain cell injury in diabetes mellitus. These different responses of neurons and astroglia may also shed new light on brain energy metabolism in diabetic patients with either chronic high or fluctuating plasma glucose concentrations.

Serum concentration of an inflammatory glycotoxin, methylglyoxal, is associated with increased cognitive decline in elderly individuals

BackgroundAdvanced glycations end products increase oxidant stress, inflammation, and neurotoxicity. Serum levels are increased in diabetes and aging. We examined the relationship between serum methylglyoxal derivatives (sMG), and cognitive decline, in 267 non-demented elderly. MethodsTobit mixed regression models assessed the association of baseline sMG with cognitive decline in the Mini Mental State Exam (MMSE) over time, controlling for sociodemographic factors (age, sex, and years of education), cardiovascular risk factors (diabetes and presence of an ApoE4 allele), and kidney function. sMG was assessed by ELISA. ResultsThe fully adjusted model showed an annual decline of 0.26 MMSE points per unit increase in baseline sMG (p=0.03). Significance was unchanged as additional risk factors were added to the model. The interactions of sMG with diabetes, sex, age, kidney function, and ApoE4 genotype were not significant. ConclusionsHigher levels of baseline sMG were associated with a faster rate of cognitive decline, after adjusting for several sociodemographic and clinical characteristics. This relationship did not differ by sex, ApoE4 genotype, or diabetes status suggesting its generality. Since subjects were cognitively normal at the beginning of the study, elevated sMG may be indicative of brain cell injury initiated before clinically evident cognitive compromise.

Comparison of diagnostic power of cerebrospinal fluid Aß and Tau variables for Alzheimer's disease diagnosis: proposition of a simple decision tree

Background: Advanced glycations endproducts (AGE) are known to cause increased oxidant stress, inflammation, and neurotoxicity; serum levels are increased in diabetes and aging. We examined the relationship between levels of serum methylglyoxal (sMG), an AGE precursor, and cognitive decline in elderly. Methods: Subjects were 266 initially non-demented elderly who had complete data including at least two MMSEs. Tobit mixed regression models assessed the association of baseline MG with cognitive decline in the Mini Mental State Exam (MMSE) score over time, controlling for sociodemographic factors (age, sex, and years of education), and cardiovascular risk factors (diabetes and presence of anAPOE4 allele). sMGwas assessed by ELISA. Results: The sample averaged 83.5 years of age, 14.3 years of education, 36 months of follow up, and 0.93 nmol/ml of sMG. Average baseline MMSE of 28.2 reflected this cognitively normal sample. Seventy six percent of the sample was male since a major source of recruitment was the Mount Sinai affiliate James J. Peters Veterans Affairs Medical Center; 18% had diabetes and 20% carried an APOE4 allele. The fully adjusted model showed an annual decline of 0.33 MMSE points per unit increase in baseline sMG (p 1⁄4 0.015). Significance improved as additional risk factors were added to the model. The interactions of sMGwith diabetes, sex, age, and APOE4 genotype were not significant and did not substantially improve the model fit. In a small replication sample of 49 younger elderly (average age 70, education 14.6, 18 months of follow up, sMG1⁄4 0.91 nmol/ml, baselineMMSE 28.8, 53%males, 13% had diabetes, 9% carried an APOE4 allele), who had a broad neuropsychological battery, results were essentially identical: for the fully adjusted model: p 1⁄4 0.01 when using the MMSE as outcome measure and p 1⁄4 0.03 when using an overall cognition outcome measure. Conclusions: Higher levels of circulating MG were associated with a faster rate of cognitive decline, after adjusting for several sociodemographic and clinical characteristics. This relationship did not differ by sex, APOE4 genotype, or diabetes status suggesting its generality. Since subjects were cognitively normal at the beginning of the study, elevated circulating MG may be indicative of brain cell injury initiated before clinically evident cognitive compromise. Because levels of MG in blood correlate with those consumed with diet, lowering MG by AGE restricted diet has potential for preventing cognitive compromise.

Perihematomal Pathological Changes in Neurons and Astrocytes Following Acute Cerebral Hemorrhage

ABSTRACTWe aim to investigate the pathological temporospatial characteristics of brain cell injury in the perihematomal areas. Brain autopsy samples from 44 consecutive cases of intracerebral hemorrhage were processed and analyzed following immunohistochemical staining for neurofilament (NF) and glial fibrillary acidic protein (GFAP). NF and GFAP positive cells were scored and graded according to the distance from the hematoma and the time from the onset of hematoma formation. The tissues from the same region on the contralateral side of the brain were used as controls. Neurons in the perihematomal areas exhibited pyknosis or swollen necrosis, while astrocytes were swollen. Morphological abnormalities pertaining to NF appearance were attenuated with increasing distance from the hematoma wall, but were exacerbated with prolonged bleeding time. The level of NF staining abnormality was positively correlated with time from the onset of hematoma within 7 days of intracerebral hemorrhage. In contrast, the intensity of GFAP staining was negatively correlated with time from the onset of hematoma formation. This immunoreactivity was significantly higher closer to hematoma. Taken together, these data indicate that pathological alterations in neurons and astrocytes in the perihematomal area change with time from the onset of hematoma formation.

Neuroglobin Protects Neurons against Oxidative Stress in Global Ischemia

Neuroglobin (Ngb) is a recently discovered globin that affords protection against hypoxic/ischemic-induced cell injury in brain. Hypoxic/ischemic injury is associated with accumulation of reactive oxygen species (ROS) and/or reactive nitrogen species (RNS). In previous studies, we found that Ngb has antioxidative properties, and protects PC-12 cells against hypoxia- and β-amyloid-induced cell death. To further delineate the potential role of Ngb in protection against cerebral ischemia-reperfusion injury in vivo, we developed a transgenic mouse line that overexpresses Ngb. Hippocampal ischemia-reperfusion injury was induced by a 10-minute bilateral occlusion of the common carotid arteries, and the animal brains were assessed 3 days later. CA1 neural injury was determined by cresyl violet staining. Lipid peroxidation was assessed using a malonyldialdehyde assay kit, whereas ROS/RNS accumulation was determined by Het staining in the CA1 hippocampal region. Hippocampal Ngb mRNA and protein expressions were assessed by reverse transcriptase-PCR and western blotting, respectively. Neuroglobin was successfully overexpressed in the hippocampus of Ngb transgenic mice. After ischemia-reperfusion, CA1 ROS/RNS production and lipid peroxidation were markedly decreased in Ngb transgenic mice compared with wild-type mice. Furthermore, CA1 neuronal injury was also markedly reduced. Thus, Ngb may confer protection against ischemia-reperfusion injury in the brain through its intrinsic antioxidant properties.

Potent Induction of IFN-α and Chemokines by Autoantibodies in the Cerebrospinal Fluid of Patients with Neuropsychiatric Lupus

Neuropsychiatric disease in systemic lupus erythematosus (NPSLE) is a poorly understood, but potentially fatal, disease manifestation. A pathogenetic role for autoantibodies is suspected, but the mechanism is unclear. Since immune complexes in SLE can stimulate IFN-alpha and there is strong evidence in humans and in mice that IFN-alpha can cause neuropsychiatric manifestations, we asked whether NPSLE patient serum and/or cerebrospinal fluid (CSF) contain abnormally high IFN-alpha-inducing activity. In a bioassay containing plasmacytoid dendritic cells and a source of Ag, NPSLE CSF induced significantly higher IFN-alpha compared with CSF from patients with multiple sclerosis or other autoimmune disease controls. When normalized for IgG concentration, NPSLE CSF was 800-fold more potent at inducing IFN-alpha compared with paired serum due to inhibitors present in serum. Analysis of Ig-deficient patient serum, depletion of IgG from normal serum, as well as addition of purified IgG to NPSLE CSF and serum in the bioassays revealed that one inhibitor was contained within the IgG fraction itself. In addition to IFN-alpha, immune complexes formed by CSF autoantibodies produced significantly increased levels of IFN-gamma-inducible protein 10 (IP-10/CXCL), IL-8, and MCP-1, all of which have been reported to be elevated in CSF from NPSLE patients. Taken together, these findings are consistent with a two-step model of NPSLE whereby CSF autoantibodies bind to Ags released by neurocytotoxic Abs or other brain cell injury, and the resulting immune complexes stimulate IFN-alpha and proinflammatory cytokines and chemokines.

Pogostemon cablin as ROS Scavenger in Oxidant‐Induced Cell Death of Human Neuroglioma Cells

Reactive oxygen species (ROS) have been implicated in the pathogenesis of a wide range of acute and long-term neurodegenerative diseases. This study was undertaken to examine the efficacy of Pogostemon cablin, a well-known herb in Korean traditional medicine, on ROS-induced brain cell injury. Pogostemon cablin effectively protected human neuroglioma cell line A172 against both the necrotic and apoptotic cell death induced by hydrogen peroxide (H2O2). The effect of Pogostemon cablin was dose dependent at concentrations ranging from 0.2 to 5 mg ml−1. Pogostemon cablin significantly prevented depletion of cellular ATP and activation of poly ADP-ribose polymerase induced by H2O2. The preservation of functional integrity of mitochondria upon the treatment of Pogostemon cablin was also confirmed by 3-(4,5-dimethyl-2-thiazyl)-2,5-diphenyl-2-H-tetrazolium bromide assay. Furthermore, Pogostemon cablin significantly prevented H2O2-induced release of cytochrome c into cytosol. Determination of intracellular ROS showed that Pogostemon cablin might exert its role as a powerful scavenger of intracellular ROS. The present study suggests the beneficial effect of Pogostemon cablin on ROS-induced neuroglial cell injury. The action of Pogostemon cablin as a ROS-scavenger might underlie the mechanism.

Brain edema and breakdown of the blood–brain barrier during methamphetamine intoxication: critical role of brain hyperthermia

To clarify the role of brain temperature in permeability of the blood-brain barrier (BBB), rats were injected with methamphetamine (METH 9 mg/kg) at normal (23 degrees C) and warm (29 degrees C) environmental conditions and internal temperatures were monitored both centrally (nucleus accumbens, NAcc) and peripherally (skin and nonlocomotor muscle). Once NAcc temperatures peaked or reached 41.5 degrees C (a level suggesting possible lethality), animals were administered Evans blue dye (protein tracer that does not normally cross the BBB), rapidly anaesthetized, perfused and had their brains removed. All METH-treated animals showed brain and body hyperthermia associated with relative skin hypothermia, suggesting metabolic activation coupled with peripheral vasoconstriction. While METH-induced NAcc temperature elevation varied from 37.60 to 42.46 degrees C (or 1.2-5.1 degrees C above baseline), it was stronger at 29 degrees C (+4.13 degrees C) than 23 degrees C (+2.31 degrees C). Relative to control, METH-treated animals had significantly higher brain levels of water, Na(+), K(+) and Cl(-), suggesting brain edema, and intense immunostaining for albumin, indicating breakdown of the BBB. METH-treated animals also showed strong immunoreactivity for glial fibrillary acidic protein (GFAP), possibly suggesting acute abnormality or damage of astrocytes. METH-induced changes in brain water, albumin and GFAP correlated linearly with NAcc temperature (r = 0.93, 0.98 and 0.98, respectively), suggesting a key role of brain hyperthermia in BBB permeability, development of brain edema and subsequent functional and structural neural abnormalities. Therefore, along with a direct destructive action on neural cells and functions, brain hyperthermia, via breakdown of the BBB, may be crucial for both decompensation of brain functions and cell injury following acute METH intoxication, possibly contributing to neurodegeneration resulting from chronic drug use.

Bone marrow stromal cells in traumatic brain injury (TBI) therapy: True perspective or false hope?

Recent studies regard bone marrow stromal cells as a potential candidate for cellular therapy of traumatic brain injury and thus as an attractive alternative for embryonic and fetal stem cells. Numerous experiments indicate that bone marrow stromal cells play an important role in the repair of injured brain tissue and also support healing processes. Findings of in vitro and in vivo studies show that these cells have an ability to differentiate into cells of multiple tissues, including neurons and glial cells and to secrete an array of growth factors and cytokines, which have an influence on repair of damaged tissue. In addition, treatment of traumatic brain injury with bone marrow stromal cells promotes functional recovery of injured animals. Taking this into consideration, there is hope for using bone marrow stromal cells in brain injury therapy, which is very difficult because of specific events that occur in the pathological conditions. However, mechanisms responsible for the observed therapeutic potential of bone marrow stromal cells still remain unclear. The review presents achievements in studies on bone marrow stromal cells as a source of therapeutic benefits in treatment of traumatic brain injury and addresses the question of their possible future use in clinical trials.