Maladaptive response following glucose overload in GLUT4-overexpressing H9C2 cardiomyoblasts.

BACKGROUND: Glucose overload drives diabetic cardiomyopathy by affecting the tricarboxylic acid pathway. However, it is still unknown how cells could overcome massive chronic glucose influx on cellular and structural level. METHODS/MATERIALS: Expression profiles of hyperglycemic, glucose transporter-4 (GLUT4) overexpressing H9C2 (KE2) cardiomyoblasts loaded with 30 mM glucose (KE230L) and wild type (WT) cardiomyoblasts loaded with 30 mM glucose (WT30L) were compared using proteomics, real-time polymerase quantitative chain reaction analysis, or Western blotting, and immunocytochemistry. RESULTS: The findings suggest that hyperglycemic insulin-sensitive cells at the onset of diabetic cardiomyopathy present complex changes in levels of structural cell-related proteins like tissue inhibitor of metalloproteases-1 (1.3 fold), intercellular adhesion molecule 1 (1.8 fold), type-IV-collagen (3.2 fold), chaperones (Glucose-Regulated Protein 78: 1.8 fold), autophagy (Autophagosome Proteins LC3A, LC3B: 1.3 fold), and in unfolded protein response (UPR; activating transcription factor 6α expression: 2.3 fold and processing: 2.4 fold). Increased f-actin levels were detectable with glucose overload by immnocytochemistry. Effects on energy balance (1.6 fold), sirtuin expression profile (Sirtuin 1: 0.7 fold, sirtuin 3: 1.9 fold, and sirtuin 6: 4.2 fold), and antioxidant enzymes (Catalase: 0.8 fold and Superoxide dismutase 2: 1.5 fold) were detected. CONCLUSION: In conclusion, these findings implicate induction of chronic cell distress by sustained glucose accumulation with a non-compensatory repair reaction not preventing final cell death. This might explain the chronic long lasting pathogenesis observed in developing heart failure in diabetes mellitus.

Açaí (Euterpe oleracea) pulp-enriched diet induces anxiolytic-like effects and improves memory retention.

Background: Açaí (Euterpe oleracea) has a rich nutritional composition, showing nutraceutical and protective effects in several organs. In this study, the effects of an açaí-enriched diet on motor performance, anxiety-like behavior, and memory retention were deeply investigated. Methods: Eight-week male Wistar rats were fed with an Euterpe oleracea (EO) pulp-enriched diet, an olive oil-enriched (OO) diet (polyunsaturated fatty acid [PUFA] fat control diet), or a chow diet for 31 days (28 days pre-treatment and 3 days during behavioral tests). Afterward, animals were submitted to a battery of behavioral tests to evaluate spontaneous motor behavior (open-field test), anxiety-like behavior (elevated plus maze and open-field test), and memory retention (step-down). Oxidative stress in the hippocampus was evaluated by a lipid peroxidation assay. Results: EO-enriched diet did not influence the body weight and food intake but increased the glucose plasmatic level after 31 days under this diet. However, a similar fat-enriched diet stimulated a marked weight gain and reduced the food intake, followed by changes in the plasmatic lipid markers. EO-enriched diet preserved the motor spontaneous performance, increased the exploration in the aversive environment (anxiolytic-like effects), and elevated the latency to step-down (improved memory retention). The EO-enriched diet also reduced the level of lipid peroxidation in the hippocampus. These positive effects of EO-enriched diet can greatly support the usage of this diet as a preventive therapy. Conclusion: Taken together, the current study suggests that Euterpe oleracea-enriched diet promotes anxiolytic-like effects and improves memory consolidation, possibly due to the reduced levels of lipid peroxidation in the hippocampus.

Calorie restriction or dietary restriction: how far they can protect the brain against neurodegenerative diseases?

Finding the correct nutritional intervention is one of the biggest challenges in treating patients with neurodegenerative diseases. In general, these patients develop strong metabolic alterations, resulting in lower treatment efficacy and higher mortality rates. However, there are still many open questions regarding the effectiveness of dietary interventions in neurodiseases. Some studies have shown that a reduction in calorie intake activates key pathways that might be important for preventing or slowing down the progression of such diseases. However, it is still unclear whether these neuroprotective effects are associated with an overall reduction in calories (hypocaloric diet) or a specific nutrient restriction (diet restriction). Therefore, here we discuss how commonly or differently hypocaloric and restricted diets modulate signaling pathways and how these changes can protect the brain against neurodegenerative diseases.

Hypocaloric Diet Initiated Post-Ischemia Provides Long-Term Neuroprotection and Promotes Peri-Infarct Brain Remodeling by Regulating Metabolic and Survival-Promoting Proteins.

Calorie restriction confers post-ischemic neuroprotection, when administered in a defined time window before ischemic stroke. How a hypocaloric diet influences stroke recovery when initiated after stroke has not been investigated. Male C57BL6/j mice were exposed to transient intraluminal middle cerebral artery occlusion. Immediately post-ischemia, mice were randomized to two groups receiving moderately hypocaloric (2286 kcal/kg food) or normocaloric (3518 kcal/kg) diets ad libitum. Animals were sacrificed at 3 or 56 days post-ischemia (dpi). Besides increased low density lipoprotein at 3 days and reduced alanine aminotransferase and increased urea at 56 days, no alterations of plasma markers were found in ischemic mice on hypocaloric diet. Body weight mildly decreased over 56 dpi by 7.4%. Hypocaloric diet reduced infarct volume in the acute stroke phase at 3 dpi and decreased brain atrophy, increased neuronal survival and brain capillary density in peri-infarct striatum and reduced motor coordination impairment in tight rope tests in the post-acute stroke phase over up to 56 dpi. The abundance of brain-derived neurotrophic factor, the NAD-dependent deacetylase and longevity protein sirtuin-1, the anti-oxidant glutathione peroxidase-3, and the ammonium detoxifier glutamine synthetase in the peri-infarct brain tissue was increased by hypocaloric diet. This study shows that a moderately hypocaloric diet that is initiated after stroke confers long-term neuroprotection and promotes peri-infarct brain remodeling.

Lipopolysaccharide-induced sepsis-like state compromises post-ischemic neurological recovery, brain tissue survival and remodeling via mechanisms involving microvascular thrombosis and brain T cell infiltration.

Sepsis predisposes for poor stroke outcome. This association suggests that sepsis disturbs post-ischemic tissue survival and brain remodeling. To elucidate this link, we herein exposed mice to 30 min intraluminal middle cerebral artery occlusion (MCAO) and induced a sepsis-like state at 72 h post-ischemia by intraperitoneal delivery of Escherichia coli lipopolysaccharide (LPS; three doses of 0.1 or 1 mg/kg, separated by 6 h), a major component of the bacterium's outer membrane. Neurological recovery, ischemic injury, brain remodeling and immune responses were evaluated over up to 56 days post-sepsis (dps) by behavioral tests, immunohistochemistry and flow cytometry. Delivery of 1 mg/kg but not 0.1 mg/kg LPS reduced rectal temperature over 48 h by up to 3.4 ± 3.1 °C, increased general and focal neurological deficits in the Clark score over 72 h and increased motor-coordination deficits in the tight rope test over up to 21 days. Notably, 1 mg/kg, but not 0.1 mg/kg LPS increased intercellular adhesion molecule-1 abundance on ischemic microvessels, increased microvascular thrombosis and increased patrolling monocyte and T cell infiltrates in ischemic brain tissue at 3 dps. Infarct volume was increased by 1 mg/kg, but not 0.1 mg/kg LPS at 3 dps (that is, 6 days post-MCAO), as was brain atrophy at 28 and 56 dps. Microglial activation in ischemic brain tissue, evaluated by morphology analysis of Iba-1 immunostainings, was transiently increased by 0.1 and 1 mg/kg LPS at 3 dps. Our data provide evidence that neurological recovery and brain remodeling are profoundly compromised in the ischemic brain post-sepsis as a consequence of cerebral thromboinflammation.

Neuroprotection Induced by Energy and Protein-Energy Undernutrition Is Phase-Dependent After Focal Cerebral Ischemia in Mice.

Malnutrition predisposes to poor stroke outcome. In animal models, undernutrition protected against ischemic injury in some, but not in other studies. In view of diverse stroke models and food restriction paradigms, the consequences of undernutrition are poorly understood. Herein, we exposed mice to energy-reduced and protein-energy-reduced diets for 7-30 days and subsequently induced intraluminal middle cerebral artery occlusion. Undernutrition phase dependently influenced ischemic injury. Short-lasting 7 days of protein-energy undernutrition, but not energy undernutrition, decreased post-ischemic brain leukocyte infiltration and microglial activation and reduced brain Il-1ß mRNA, but did not protect against ischemic injury. Fourteen days of energy and protein-energy undernutrition, on the other hand, reduced ischemic injury despite absence of anti-inflammatory effects. Anti-oxidant genes (Sod-1, Sod-2, and Cat mRNAs) were regulated in the liver and, to a lesser extent, the ischemic brain, indicating an adapted, compensated stage. Conversely, 30 days of energy and protein-energy undernutrition caused progressive animal exhaustion associated with post-ischemic hypoperfusion, rise of metabolic markers (Sirt-1 and Glut-1 mRNAs, Sirt-1 protein) in the ischemic brain, and reregulation of pro- and anti-oxidant markers (now also Nox-4 and Gpx-3 mRNAs) in the liver. In the latter condition, no neuroprotection was noted. Our study suggests an adaptation of metabolic systems that provides neuroprotection in a circumscribed time window.

Oxidative Stress Mediates Anxiety-Like Behavior Induced by High Caffeine Intake in Zebrafish: Protective Effect of Alpha-Tocopherol.

Anxiety is a common symptom associated with high caffeine intake. Although the neurochemical mechanisms of caffeine-induced anxiety remain unclear, there are some evidences suggesting participation of oxidative stress. Based on these evidences, the current study is aimed at evaluating the possible protective effect of alpha-tocopherol (TPH) against anxiety-like behavior induced by caffeine (CAF) in zebrafish. Adult animals were treated with CAF (100 mg/kg) or TPH (1 mg/kg)+CAF before behavioral and biochemical evaluations. Oxidative stress in the zebrafish brain was evaluated by a lipid peroxidation assay, and anxiety-like behavior was monitored using light/dark preference and novel tank diving test. Caffeine treatment evoked significant elevation of brain MDA levels in the zebrafish brain, and TPH treatment prevented this increase. Caffeine treatment also induced anxiety-like behavior, while this effect was not observed in the TPH+CAF group. Taken together, the current study suggests that TPH treatment is able to inhibit oxidative stress and anxiety-like behavior evoked by caffeine.

Moderate Protein Restriction Protects Against Focal Cerebral Ischemia in Mice by Mechanisms Involving Anti-inflammatory and Anti-oxidant Responses.

Food composition influences stroke risk, but its effects on ischemic injury and neurological deficits are poorly examined. While severe reduction of protein content was found to aggravate neurological impairment and brain injury as a consequence of combined energy-protein malnutrition, moderate protein restriction not resulting in energy deprivation was recently suggested to protect against perinatal hypoxia-ischemia. Male C57BL6/j mice were exposed to moderate protein restriction by providing a normocaloric diet containing 8% protein (control: 20% protein) for 7, 14, or 30 days. Intraluminal middle cerebral artery occlusion was then induced. Mice were sacrificed 24 h later. Irrespective of the duration of food modification (that is, 7-30 days), protein restriction reduced neurological impairment of ischemic mice revealed by a global and focal deficit score. Prolonged protein restriction over 30 days also reduced infarct volume, brain edema, and blood-brain barrier permeability and increased the survival of NeuN+ neurons in the core of the stroke (i.e., striatum). Neuroprotection by prolonged protein restriction went along with reduced brain infiltration of CD45+ leukocytes and reduced expression of inducible NO synthase and interleukin-1ß. As potential mechanisms, increased levels of the NAD-dependent deacetylase sirtuin-1 and anti-oxidant glutathione peroxidase-3 were noted in ischemic brain tissue. Irrespective of the protein restriction duration, a shift from pro-oxidant oxidative stress markers (NADPH oxidase-4) to anti-oxidant markers (superoxide dismutase-1/2, glutathione peroxidase-3 and catalase) was found in the liver. Moderate protein restriction protects against ischemia in the adult brain. Accordingly, dietary modifications may be efficacious strategies promoting stroke outcome.

Diet enriched with the Amazon fruit açaí (Euterpe oleracea) prevents electrophysiological deficits and oxidative stress induced by methyl-mercury in the rat retina.

BACKGROUND: The protective effect of a diet supplemented by the Amazonian fruit Euterpe oleracea (EO) against methylmercury (MeHg) toxicity in rat retina was studied using electroretinography (ERG) and biochemical evaluation of oxidative stress. METHOD: Wistar rats were submitted to conventional diet or EO-enriched diet for 28 days. After that, each group received saline solution or 5 mg/kg/day of MeHg for 7 days. Full-field single flash, flash and flicker ERGs were evaluated in the following groups: control, EO, MeHg, and EO+MeHg. The amplitudes of the a-wave, b-wave, photopic negative response from rod and/or cone were measured by ERGs as well as the amplitudes and phases of the fundamental component of the sine-wave flicker ERG. Lipid peroxidation was determined by thiobarbituric acid reactive species. RESULTS: All ERG components had decreased amplitudes in the MeHg group when compared with controls. EO-enriched food had no effect on the non-intoxicated animals. The intoxicated animals and those that received the supplemented diet presented significant amplitude reductions of the cone b-wave and of the fundamental flicker component when compared with non-intoxicated control. The protective effect of the diet on scotopic conditions was only observed for bright flashes eliciting a mixed rod and cone response. There was a significant increase of lipid peroxidation in the retina from animals exposed to MeHg and EO-supplemented diet was able to prevent MeHg-induced oxidative stress in retinal tissue. CONCLUSION: These findings open up perspectives for the use of diets supplemented with EO as a protective strategy against visual damage induced by MeHg.

Methods for the analysis of neuronal plasticity and brain connectivity during neurological recovery.

The study of neuronal plasticity under pathological conditions is now a major point of focus on the field of neurological recovery. After the repeated failure of acute neuroprotection strategies for stroke treatment, the design of studies aimed at promoting the reconstruction of neuronal networks has become essential. Methods for the delivery of therapeutic agents on a steady dosage, thus preventing pharmacological peaks or excessive manipulation of experimental animals, are thus required. Additionally, methods that allow the visualization of neurological remodeling processes are fundamental to the understanding of how a therapeutic agent exerts its function. Here we describe how the use of miniosmotic pumps for the steady delivery of such agents, together with tract tracer injections, can be combined to unveil important information on how the brain changes after stroke and how therapeutic agents promote brain remodeling recovery.

Non-mammalian models in behavioral neuroscience: consequences for biological psychiatry.

Current models in biological psychiatry focus on a handful of model species, and the majority of work relies on data generated in rodents. However, in the same sense that a comparative approach to neuroanatomy allows for the identification of patterns of brain organization, the inclusion of other species and an adoption of comparative viewpoints in behavioral neuroscience could also lead to increases in knowledge relevant to biological psychiatry. Specifically, this approach could help to identify conserved features of brain structure and behavior, as well as to understand how variation in gene expression or developmental trajectories relates to variation in brain and behavior pertinent to psychiatric disorders. To achieve this goal, the current focus on mammalian species must be expanded to include other species, including non-mammalian taxa. In this article, we review behavioral neuroscientific experiments in non-mammalian species, including traditional "model organisms" (zebrafish and Drosophila) as well as in other species which can be used as "reference." The application of these domains in biological psychiatry and their translational relevance is considered.