Grape seed proanthocyanidin extract inhibits glutamate-induced cell death through inhibition of calcium signals and nitric oxide formation in cultured rat hippocampal neurons

Advancements in a FRET Biosensor for Live-Cell Fluorescence-Lifetime High-Throughput Screening of Alpha-Synuclein

There is a critical need for small molecules capable of rescuing pathophysiological phenotypes induced by alpha-synuclein (aSyn) misfolding and oligomerization. Building upon our previous aSyn cellular fluorescence lifetime (FLT)-Förster resonance energy transfer (FRET) biosensors, we have developed an inducible cell model incorporating the red-shifted mCyRFP1/mMaroon1 (OFP/MFP) FRET pair. This new aSyn FRET biosensor improves the signal-to-noise ratio, reduces nonspecific background FRET, and results in a 4-fold increase (transient transfection) and 2-fold increase (stable, inducible cell lines) in FRET signal relative to our previous GFP/RFP aSyn biosensors. The inducible system institutes greater temporal control and scalability, allowing for fine-tuning of biosensor expression and minimizes cellular cytotoxicity due to overexpression of aSyn. Using these inducible aSyn-OFP/MFP biosensors, we screened the Selleck library of 2684 commercially available, FDA-approved compounds and identified proanthocyanidins and casanthranol as novel hits. Secondary assays validated the ability of these compounds to modulate aSyn FLT-FRET. Functional assays probing cellular cytotoxicity and aSyn fibrillization demonstrated their capability to inhibit seeded aSyn fibrillization. Proanthocyanidins completely rescued aSyn fibril-induced cellular toxicity with EC50 of 200 nM and casanthranol supported a 85.5% rescue with a projected EC50 of 34.2 μM. Furthermore, proanthocyanidins provide a valuable tool compound to validate our aSyn biosensor performance in future high-throughput screening campaigns of industrial-scale (million-compound) chemical libraries.

A resveratrol derivative modulates TRH and TRH ‐like peptide expression throughout the brain and peripheral tissues of male rats

Introduction

Methods

Results

Conclusion

Effects of dietary grape seed proanthocyanidin extract supplementation on meat quality, muscle fiber characteristics and antioxidant capacity of finishing pigs

The aim of this study was to investigate effects of dietary grape seed proanthocyanidin extract (GSPE) supplementation on meat quality, muscle fiber characteristics and antioxidant capacity of finishing pigs. The data showed GSPE increased pH24 h, redness, crude protein content and decreased shear force, drip loss48 h, lactate content and glycolytic potential in longissimus dorsi (LD) muscle, accompanied by increased contents of total polyunsaturated fatty acid (PUFA), n-3 PUFA, and the ratio of PUFA to saturated fatty acid. GSPE promoted MyHC I mRNA and slow MyHC protein expression, and increased slow-twitch fiber percentage. The activities of total antioxidant capacity, total superoxide dismutase, catalase and glutathione peroxidase in LD muscle were increased by GSPE while malondialdehyde content was decreased. Together, this study demonstrated that dietary GSPE supplementation can effectively improve the color, water-holding capacity, tenderness and nutritional value of pork, and increase slow-twitch fiber percentage and antioxidant capacity of finishing pigs.

Change of Serum Metabolome and Cecal Microflora in Broiler Chickens Supplemented With Grape Seed Extracts

Grape seed is rich in vitamin E, flavonoids, and proanthocyanidins and has the potential to be used as an antibiotic substitute in broilers. We investigated the effects of grape seed proanthocyanidin extract (GSPE) on growth performance, immune responses, cecal microflora, and serum metabolism in early stage broilers. Data indicated that GSPE improved broiler growth performance by strengthening antioxidant capacity, enhancing immune responses, and increasing cecal short chain fatty acids. 16S rRNA sequencing indicated that GSPE changed the predominant cecal microflora and induced the metabolism of amino acids, lipids, and carbohydrates. An UPLC-Q-TOF/MS-based metabolomics analysis identified 23 serum metabolites (mainly related to lipid, amino acid, and alkaloid) were extremely changed by GSPE treatment. The correlations between the changes of cecal microflora and serum metabolites in birds fed with GSPE were analyzed. Hence, GSPE potentially provides active ingredients that may be used as antibiotic substitute and reduces environmental pollution by grape by-products.

Preventive and curative effects of grape seed powder on stroke using in vitro and in vivo models of cerebral ischemia/reperfusion

Stroke is a worldwide concern. Many studies pointed out relevant preventive effect of grape seed powder (GSP) against deleterious brain ischemia/reperfusion (I/R) injury, but curative effect has been scarcely approached. The present work aimed at studying the preventive and curative effect of GSP against stroke using in-vitro and in-vivo models. Primary neuron-astrocyte cocultures were used to evaluate in-vitro GSP protective and curative effect on oxygen-glucose-deprivation (OGD). A murine I/R model, in which GSP was administered as delayed post stroke drug, to evaluate its potential clinically translatable therapy was used and behavioral tests were conducted after 15 days. Ultra-structure of hippocampus dentate gyrus using Transmission Electron Microscopy (TEM) was also undertaken. GSP prevented OGD-induced toxicity and cell death in a dose dependent manner and was neuroprotective as assessed by sustained cell viability (70 % ±1 for OGD + GSP and 37 % ±2 for OGD) and modulated cytokines and brain derived neurotrophic factor (BDNF) expression. GSP also promoted behavioral outcomes by increasing step-down inhibitory time from 17s±4 to 50s±11 and rat overall activities by improving scores in open field test to near control level. Furthermore, GSP protected hippocampus dentate gyrus area from I/R-induced drastic alterations as assessed by reduced autophagic vacuoles.

Accelerated cancer aggressiveness by viral oncomodulation: New targets and newer natural treatments for cancer control and treatment

An infectious etiology for a number of cancers has been entertained for over 100 years and modern studies have confirmed that a number of viruses are linked to cancer induction. While a large number of viruses have been demonstrated in a number of types of cancers, most such findings have been dismissed in the past as opportunistic infections, especially with persistent viruses with high rates of infectivity of the world’s populations. More recent studies have clearly shown that while not definitely causing these cancers, these viruses appear capable of affecting the biology of these tumors in such a way as to make them more aggressive and more resistant to conventional treatments. The term oncomodulatory viruses has been used to describe this phenomenon. A number of recent studies have shown a growing number of ways these oncomodulatory viruses can alter the pathology of these tumors by affecting cell-signaling, cell metabolism, apoptosis mechanisms, cell-cell communication, inflammation, antitumor immunity suppression, and angiogenesis. We are also learning that much of the behavior of tumors depends on cancer stem cells and stromal cells within the tumor microenvironment, which participate in extensive, dynamic crosstalk known to affect tumor behavior. Cancer stem cells have been found to be particularly susceptible to infection by human cytomegalovirus. In a number of studies, it has been shown that while only a select number of cells are actually infected with the virus, numerous viral proteins are released into cancer and stromal cells in the microenvironment and these viral proteins are known to affect tumor behavior and aggressiveness.

Combined actions of blueberry extract and lithium on neurochemical changes observed in an experimental model of mania: exploiting possible synergistic effects

Bipolar disorder is a psychiatric disease characterized by recurrent episodes of mania and depression. Blueberries contain bioactive compounds with important pharmacological effects such as neuroprotective and antioxidant actions. The aim of this study was to investigate the effects of blueberry extract and/or lithium on oxidative stress, and acetylcholinesterase (AChE) and Na⁺, K⁺-ATPase activity in an experimental ketamine-induced model of mania. Male Wistar rats were pretreated with vehicle, blueberry extract (200 mg/kg), and/or lithium (45 mg/kg or 22.5 mg/kg twice daily) for 14 days. Between the 8th and 14th days, the animals also received an injection of ketamine (25 mg/kg) or vehicle. On the 15th day the animals received a single injection of ketamine; after 30 min, the locomotor activity was evaluated in an open field test. Ketamine administration induced an increase in locomotor activity. In the cerebral cortex, hippocampus and striatum, ketamine also induced an increase in reactive oxygen species, lipid peroxidation and nitrite levels, as well a decrease in antioxidant enzyme activity. Pretreatment with blueberry extract or lithium was able to prevent this change. Ketamine increased the AChE and Na⁺, K⁺-ATPase activity in brain structures, while the blueberry extract partially prevented these alterations. In addition, our results showed that the neuroprotective effect was not potentiated when lithium and blueberry extract treatment were given together. In conclusion, our findings suggest that blueberry extract has a neuroprotective effect against an experimental model of mania. However, more studies should be performed to evaluate its effects as an adjuvant therapy.

Proanthocyanidins Alleviates AflatoxinB₁-Induced Oxidative Stress and Apoptosis through Mitochondrial Pathway in the Bursa of Fabricius of Broilers

Aflatoxin B₁ (AFB₁) is a serious threat to the poultry industry. Proanthocyanidins (PCs) demonstrates a broad range of biological, pharmacological, therapeutic, and chemoprotective properties. The aim of this study was to investigate the ameliorative effects of PCs against AFB₁-induced histopathology, oxidative stress, and apoptosis via the mitochondrial pathway in the bursa of Fabricius (BF) of broilers. One hundred forty-four one-day old Cobb chicks were randomly assigned into four treatment groups of six replicates (6 birds each replicate) for 28 days. Groups were fed on the following four diets; (1) Basal diet without addition of PCs or AFB₁ (Control); (2) basal diet supplemented with 1 mg/kg AFB₁ from contaminated corn (AFB₁); (3) basal diet supplemented with 250 mg/kg PCs (PCs); and (4) basal diet supplemented with 1 mg/kg AFB₁ + 250 mg/kg PCs (AFB₁+ PCs). The present study results showed that antioxidant enzymes activities of total superoxide dismutase (T-SOD), catalase (CAT), glutathione peroxidase (GSH-Px), and glutathione S-transferase (GST) in AFB₁ treated group were (p < 0.05) decreased, whereas malondialdehyde (MDA) contents were significantly increased in comparison with the control group. Furthermore, we found that dietary PCs treatment ameliorated AFB₁-induced oxidative stress in the BF through inhibiting the accumulation of MDA content and enhancing the antioxidant enzymes activities (T-SOD, CAT, GSH-Px, and GST). Similarly, PCs markedly enhanced messenger RNA (mRNA) expression of antioxidant genes (SOD, CAT, GPx1, and GST) in comparison with AFB₁ group. Moreover, histological results showed that PCs alleviated AFB₁-induced apoptotic cells in the BF of broilers. In addition, both mRNA and protein expression results manifested that mitochondrial-apoptosis-associated genes (Bax, caspase-9, caspase-3, and p53 and cytochrome c) showed up-regulation, while (Bcl-2) showed down-regulation in AFB₁ fed group. The supplementation of PCs to AFB₁ diet significantly reversed the mRNA and protein expression of these apoptosis-associated genes, as compared to the AFB₁ group. Our results demonstrated that PCs ameliorated AFB₁-induced oxidative stress by modulating the antioxidant defense system and apoptosis in the BF through mitochondrial pathway in broilers.

Cyanidin-3-glucoside inhibits amyloid β25-35-induced neuronal cell death in cultured rat hippocampal neurons

Increasing evidence implicates changes in [Ca²⁺]_i and oxidative stress as causative factors in amyloid beta (Aβ)-induced neuronal cell death. Cyanidin-3-glucoside (C3G), a component of anthocyanin, has been reported to protect against glutamate-induced neuronal cell death by inhibiting Ca²⁺ and Zn²⁺ signaling. The present study aimed to determine whether C3G exerts a protective effect against Aβ_25–35-induced neuronal cell death in cultured rat hippocampal neurons from embryonic day 17 fetal Sprague-Dawley rats using MTT assay for cell survival, and caspase-3 assay and digital imaging methods for Ca²⁺, Zn²⁺, MMP and ROS. Treatment with Aβ_25–35 (20 µM) for 48 h induced neuronal cell death in cultured rat pure hippocampal neurons. Treatment with C3G for 48 h significantly increased cell survival. Pretreatment with C3G for 30 min significantly inhibited Aβ_25–35-induced [Zn²⁺]_i increases as well as [Ca²⁺]_i increases in the cultured rat hippocampal neurons. C3G also significantly inhibited Aβ_25–35-induced mitochondrial depolarization. C3G also blocked the Aβ_25–35-induced formation of ROS. In addition, C3G significantly inhibited the Aβ_25–35-induced activation of caspase-3. These results suggest that cyanidin-3-glucoside protects against amyloid β-induced neuronal cell death by reducing multiple apoptotic signals.

Bona fide receptor for hepatitis B and D viral infections: Mechanism, research models and molecular drug targets

Hepatitis B infections have become a serious public health issue globally, and the current first-line antiviral treatment for this disease is not a true cure. Recently, sodium taurocholate cotransporting polypeptide (NTCP), a liver-specific bile acid transporter, was identified as a bona fide receptor for hepatitis B virus (HBV) and its satellite virus, hepatitis delta virus (HDV). Identification of the HBV receptor has led to the development of robust cell cultures and provides a potential target for new treatments. This review summarizes the process by which NTCP was discovered and describes its clinical significance as the receptor for HBV and HDV entry.

Ameliorative Effects of Grape Seed Proanthocyanidin Extract on Growth Performance, Immune Function, Antioxidant Capacity, Biochemical Constituents, Liver Histopathology and Aflatoxin Residues in Broilers Exposed to Aflatoxin B₁

Aflatoxicosis is a grave threat to the poultry industry. Dietary supplementation with antioxidants showed a great potential in enhancing the immune system; hence, protecting animals against aflatoxin B₁-induced toxicity. Grape seed proanthocyanidin extract (GSPE) one of the most well-known and powerful antioxidants. Therefore, the purpose of this research was to investigate the effectiveness of GSPE in the detoxification of AFB₁ in broilers. A total of 300 one-day-old Cobb chicks were randomly allocated into five treatments of six replicates (10 birds per replicate), fed ad libitum for four weeks with the following dietary treatments: 1. Basal diet (control); 2. Basal diet + 1 mg/kg AFB₁ contaminated corn (AFB₁); 3. Basal diet + GSPE 250 mg/kg; (GSPE 250 mg/kg) 4. Basal diet + AFB₁ (1 mg/kg) + GSPE 250 mg/kg; (AFB₁ + GSPE 250 mg/kg) 5. Basal diet + AFB₁ (1mg/kg) + GSPE 500 mg/kg, (AFB₁ + GSPE 500 mg/kg). When compared with the control group, feeding broilers with AFB₁ alone significantly reduced growth performance, serum immunoglobulin contents, negatively altered serum biochemical contents, and enzyme activities, and induced histopathological lesion in the liver. In addition, AFB₁ significantly increased malondialdehyde content and decreased total superoxide dismutase, catalase, glutathione peroxide, glutathione-S transferase, glutathione reductase activities, and glutathione concentration within the liver and serum. The supplementation of GSPE (250 and 500 mg/kg) to AFB₁ contaminated diet reduced AFB₁ residue in the liver and significantly mitigated AFB₁ negative effects. From these results, it can be concluded that dietary supplementation of GSPE has protective effects against aflatoxicosis caused by AFB₁ in broiler chickens.

Amperometric Microsensors Monitoring Glutamate-Evoked In Situ Responses of Nitric Oxide and Carbon Monoxide from Live Human Neuroblastoma Cells

In the brain, nitric oxide (NO) and carbon monoxide (CO) are important signaling gases which have multifaceted roles, such as neurotransmitters, neuromodulators, and vasodilators. Even though it is difficult to measure NO and CO in a living system due to their high diffusibility and extremely low release levels, electrochemical sensors are promising tools to measure in vivo and in vitro NO and CO gases. In this paper, using amperometric dual and septuple NO/CO microsensors, real-time NO and CO changes evoked by glutamate were monitored simultaneously for human neuroblastoma (SH-SY5Y) cells. In cultures, the cells were differentiated and matured into functional neurons by retinoic acid and brain-derived neurotrophic factor. When glutamate was administrated to the cells, both NO and CO increases and subsequent decreases returning to the basal levels were observed with a dual NO/CO microsensor. In order to facilitate sensor’s measurement, a flower-type septuple NO/CO microsensor was newly developed and confirmed in terms of the sensitivity and selectivity. The septuple microsensor was employed for the measurements of NO and CO changes as a function of distances from the position of glutamate injection. Our sensor measurements revealed that only functionally differentiated cells responded to glutamate and released NO and CO.

A new class of hepatitis B and D virus entry inhibitors, proanthocyanidin and its analogs, that directly act on the viral large surface proteins

Introduction of direct-acting antivirals against hepatitis C virus (HCV) has provided a revolutionary improvement in the treatment outcome. In contrast to HCV, however, the strategy for developing new antiviral agents against hepatitis B virus (HBV), especially viral-targeting compounds, is limited because HBV requires only four viral genes for its efficient replication/infection. Here, we identify an oligomeric flavonoid, proanthocyanidin (PAC) and its analogs, which inhibit HBV entry into host cells by targeting the HBV large surface protein (LHBs). Through cell-based chemical screening, PAC was identified to inhibit HBV infection with little cytotoxic effect. PAC prevented the attachment of the preS1 region in the LHBs to its cellular receptor, sodium taurocholate cotransporting polypeptide (NTCP). PAC was shown to target HBV particles and impair their infectivity, whereas it did not affect the NTCP-mediated bile acid transport activity. Chemical biological techniques demonstrated that PAC directly interacted with the region essential for receptor binding in the preS1 region in the LHBs protein. Importantly, PAC had a pan-genotypic anti-HBV activity and was also effective against a clinically relevant nucleoside analog-resistant HBV isolate. We further showed that PAC augmented the ability of a nucleoside analog, tenofovir, to interrupt HBV spread over time in primary human hepatocytes by cotreatment. Moreover, derivative analysis could identify small molecules that demonstrated more-potent anti-HBV activity over PAC.

CONCLUSION

PAC and its analogs represent a new class of anti-HBV agents that directly target the preS1 region of the HBV large surface protein. These agents could contribute to the development of a potent, well-tolerated, and broadly active inhibitor of HBV infection. (Hepatology 2017;65:1104-1116).

Grape seed proanthocyanidin extract protects lymphocytes against histone-induced apoptosis

Apoptosis of lymphocytes is associated with immunosuppression and poor prognosis in sepsis. Our previous report showed that histones, nuclear proteins released from damaged or dying cells in sepsis, can mediate lymphocyte apoptosis via mitochondria damage. Grape seed proanthocyanidin extract (GSPE), a natural substance with protective properties against oxidative stress, plays a vital role in cell and mitochondria protection. We thus hypothesized that GSPE may play a protective role in histone-induced lymphocyte apoptosis through its anti-oxidative properties. In this study, we investigated the protective efficacy of GSPE on lymphocyte apoptosis induced by extracellular histones, a main contributor of death in sepsis. Human blood lymphocytes were treated with 50 μg/ml histones, 2 μg/ml GSPE, or a combination of both. A total of 100 μM N-acetylcysteine (NAC), a reactive oxygen species (ROS) inhibitor, was used as a positive control for GSPE. Apoptosis, intracellular ROS levels, mitochondrial membrane potential, Bcl-2 expression, and caspase-3 cleavage were measured. Our data clearly indicate that GSPE significantly inhibited lymphocyte apoptosis, generation of ROS, the loss of mitochondrial membrane potential, the decrease in Bcl-2 expression, and caspase-3 activation induced by extracellular histones. In conclusion, we show that GSPE has a protective effect on lymphocyte apoptosis induced by extracellular histones. This study suggests GSPE as a potential therapeutic agent that could help reduce lymphocyte apoptosis, and thus the state of immunosuppression was observed in septic patients.

Grape seed proanthocyanidin extracts prevent high glucose-induced endothelia dysfunction via PKC and NF-κB inhibition

In our study, it has been detected in vivo and in vitro that GSPE reversed high glucose-induced the increase of ICAM-1 and VCAM-1. It is shown that by western blotting detection, GSPE significantly inhibited the activation of NF-κB induced by high glucose while there was significant decrease of the expression of PKC with GSPE intervention. By adding the NF-κB blocker PDTC and the PKC inhibitor peptide 19–31(10−6 M), no significant difference was found in the levels of VCAM-1 and ICAM-1 among GSPE group, the PKC inhibitor peptide 19–31-added GSPE group and the PDTC-added GSPE group. So the conclusion could be drawn that PKC inhibition must be involved in GSPE decreasing the level of ICAM-1 and VCAM-1.We proved for the first time that GSPE prevented high glucose-induced the increase of ICAM-1 and VCAM-1 by PKC and NF-κB inhibition. These findings show a novel mechanism of the action GSPE preventing endothelial dysfunction, which may have clinical application values.

The role of multifunctional drug therapy against carbamate induced neuronal toxicity during acute and chronic phase in rats

The current study has been designed to examine the effect of multifunctional drug therapy on carbofuran induced acute (2.187 mg/kg, s.c.) and sub-acute (0.2187 mg/kg, s.c.) neurotoxicity in male wistar rats. Drug treatment which includes nimodipine (Ca(2+) channel blocker), diazepam, ropinirole (dopamine agonist) and GSPE (antioxidant) was started 2h after carbofuran administration. Morris water maze was employed for aiming spatial memory. Narrow beam walk and rotarod were employed for testing motor functions. Brain acetylcholinesterase activity, thiobarbituric acid reactive species, nitrite, reduced glutathione, catalase levels, and mitochondrial complexes were also estimated. Carbofuran treatment resulted in significant development of cognitive and motor functions manifested as impairment in learning and memory along with increased thiobarbituric acid reactive species, nitrite levels and decreased acetylcholinesterase activity, reduced glutathione, catalase levels, and mitochondrial complexes. The standard antidote therapy (atropine) was not able to provide neuroprotection but was able to provide symptomatic relief. The multifunctional drug therapy attenuated carbofuran induced cognitive and motor dysfunction, acetylcholinesterase activity and other biochemical parameters. The triple combination in sub-acute study may be avoided in future as two drug combinations provide adequate neuroprotection. Thus it can be concluded that standard antidotal therapy may not provide neuroprotection while the multifunctional drug therapy offers neuroprotection against carbofuran and may dramatically increase survival and life quality.

Cyanidin-3-glucoside inhibits glutamate-induced Zn2+ signaling and neuronal cell death in cultured rat hippocampal neurons by inhibiting Ca2+-induced mitochondrial depolarization and formation of reactive oxygen species

Cyanidin-3-glucoside (C3G), a member of the anthocyanin family, is a potent natural antioxidant. However, effects of C3G on glutamate-induced [Zn(2+)]i increase and neuronal cell death remain unknown. We studied the effects of C3G on glutamate-induced [Zn(2+)]i increase and cell death in cultured rat hippocampal neurons from embryonic day 17 maternal Sprague-Dawley rats using digital imaging methods for Zn(2+), Ca(2+), reactive oxygen species (ROS), mitochondrial membrane potential and a MTT assay for cell survival. Treatment with glutamate (100 µM) for 7 min induces reproducible [Zn(2+)]i increase at 35 min interval in cultured rat hippocampal neurons. The intracellular Zn(2+)-chelator TPEN markedly blocked glutamate-induced [Zn(2+)]i increase, but the extracellular Zn(2+) chelator CaEDTA did not affect glutamate-induced [Zn(2+)]i increase. C3G inhibited the glutamate-induced [Zn(2+)]i response in a concentration-dependent manner (IC50 of 14.1 ± 1.1 µg/ml). C3G also significantly inhibited glutamate-induced [Ca(2+)]i increase. Two antioxidants such as Trolox and DTT significantly inhibited the glutamate-induced [Zn(2+)]i response, but they did not affect the [Ca(2+)]i responses. C3G blocked glutamate-induced formation of ROS. Trolox and DTT also inhibited the formation of ROS. C3G significantly inhibited glutamate-induced mitochondrial depolarization. However, TPEN, Trolox and DTT did not affect the mitochondrial depolarization. C3G, Trolox and DTT attenuated glutamate-induced neuronal cell death in cultured rat hippocampal neurons, respectively. Taken together, all these results suggest that cyanidin-3-glucoside inhibits glutamate-induced [Zn(2+)]i increase through a release of Zn(2+) from intracellular sources in cultured rat hippocampal neurons by inhibiting Ca(2+)-induced mitochondrial depolarization and formation of ROS, which is involved in neuroprotection against glutamate-induced cell death.

Protective effect of grape seed and skin extract on cerebral ischemia in rat: implication of transition metals

Ischemic stroke is a leading cause of long lasting disability in humans and oxidative stress an important underlying cause. The present study aims to determine the effect of short term (seven-days) administration of high dosage grape seed and skin extract (GSSE 2.5 g/kg) on ischemia/reperfusion (I/R) injury in a rat model of global ischemia. Ischemia was induced by occlusion of the common carotid arteries for 30 min followed by one-hour reperfusion on control or GSSE treated animals. I/R induced a drastic oxidative stress characterized by high lipid and protein oxidation, a drop in antioxidant enzyme defenses, disturbed transition metals as free iron overload and depletion of copper, zinc and manganese as well as of associated brain enzyme activities as glutamine synthetase and lactate dehydrogenase. I/R also induced NO and calcium disruption and an increase in calpain activity, a calcium-sensitive cysteine protease. Interestingly, almost all I/R-induced disturbances were prevented by GSSE pretreatment as oxidative stress, transition metals associated enzyme activities, brain damage size and histology. Owing to its antioxidant potential, high dosage GSSE protected efficiently the brain against ischemic stroke and should be translated to humans.

Grape seed extract has superior beneficial effects than vitamin E on oxidative stress and apoptosis in the hippocampus of streptozotocin induced diabetic rats

We aimed to investigate the effects of grape seed extract (GSE) and vitamin E (Vit E) on oxidative stress and apoptosis in the hippocampus of streptozotocin-induced diabetic rats. In Control, Diabetic, and Diabetic treated with GSE (Diabetic+GSE) and vitamin E (Diabetic+Vit E) groups, oxidative stress index (OSI), TUNEL staining and Bcl-2, Bcl-XL, Bax, caspase-3, -9, and -8, Cyt-c, TNF-α, and NF-κB gene expressions were evaluated. OSI was significantly increased in the plasma and hippocampus of the Diabetic compared to Control group and decreased in Diabetic+GSE and Diabetic+Vit E groups compared to Diabetic. TUNEL positive neurons significantly increased in the hippocampus of the Diabetic group compared to Control and decreased in Diabetic+GSE (more prominently) and Diabetic+Vit E groups compared to Diabetic. In the hippocampus of the Diabetic group, Bcl-2 and Bcl-XL gene expressions were significantly decreased; Bax, caspase-3, -9, and -8, Cyt-c, TNF-α, and NF-κB gene expressions were significantly increased compared to Control. In Diabetic+GSE and Diabetic+Vit E groups, Bcl-2 gene expressions were significantly increased; Bcl-XL gene expressions did not differ compared to the Diabetic group. The expression of Bax, caspase-3, -9, and -8, Cyt-c, TNF-α, and NF-κB genes in the Diabetic+GSE group and the expression of caspase-3 and -9, TNF-α, and NF-κB genes in the Diabetic+Vit E group were significantly decreased compared to Diabetic. In conclusion, GSE (more prominently) and vitamin E decreased oxidative stress and neuronal apoptosis occurring in the hippocampus of diabetic rats.

Oligomeric proanthocyanidin protects retinal ganglion cells against oxidative stress-induced apoptosis

The death of retinal ganglion cells is a hallmark of many optic neurodegenerative diseases such as glaucoma and retinopathy. Oxidative stress is one of the major reasons to cause the cell death. Oligomeric proanthocyanidin has many health beneficial effects including antioxidative and neuroprotective actions. Here we tested whether oligomeric proanthocyanidin may protect retinal ganglion cells against oxidative stress induced-apoptosis in vitro. Retinal ganglion cells were treated with hydrogen peroxide with or without oligomeric proanthocyanidin. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay showed that treating retinal ganglion cell line RGC-5 cells with 20 μmol/L oligomeric proanthocyanidin significantly decreased the hydrogen peroxide (H2O2) induced death. Results of flow cytometry and Hoechst staining demonstrated that the death of RGC-5 cells was mainly caused by cell apoptosis. We further found that expression of pro-apoptotic Bax and caspase-3 were significantly decreased while anti-apoptotic Bcl-2 was greatly increased in H2O2 damaged RGC-5 cells with oligomeric proanthocyanidin by western blot assay. Furthermore, in retinal explant culture, the number of surviving retinal ganglion cells in H2O2-damaged retinal ganglion cells with oligomeric proanthocyanidin was significantly increased. Our studies thus demonstrate that oligomeric proanthocyanidin can protect oxidative stress-injured retinal ganglion cells by inhibiting apoptotic process.

Cyanidin-3-glucoside Inhibits ATP-induced Intracellular Free Ca(2+) Concentration, ROS Formation and Mitochondrial Depolarization in PC12 Cells

Flavonoids have an ability to suppress various ion channels. We determined whether one of flavonoids, cyanidin-3-glucoside, affects adenosine 5'-triphosphate (ATP)-induced calcium signaling using digital imaging methods for intracellular free Ca(2+) concentration ([Ca(2+)]i), reactive oxygen species (ROS) and mitochondrial membrane potential in PC12 cells. Treatment with ATP (100µM) for 90 sec induced [Ca(2+)]i increases in PC12 cells. Pretreatment with cyanidin-3-glucoside (1µ g/ml to 100µg/ml) for 30 min inhibited the ATP-induced [Ca(2+)]i increases in a concentration-dependent manner (IC50=15.3µg/ml). Pretreatment with cyanidin-3-glucoside (15µg/ml) for 30 min significantly inhibited the ATP-induced [Ca(2+)]i responses following removal of extracellular Ca(2+) or depletion of intracellular [Ca(2+)]i stores. Cyanidin-3-glucoside also significantly inhibited the relatively specific P2X2 receptor agonist 2-MeSATP-induced [Ca(2+)]i responses. Cyanidin-3-glucoside significantly inhibited the thapsigargin or ATP-induced store-operated calcium entry. Cyanidin-3-glucoside significantly inhibited the ATP-induced [Ca(2+)]i responses in the presence of nimodipine and ω-conotoxin. Cyanidin-3-glucoside also significantly inhibited KCl (50 mM)-induced [Ca(2+)]i increases. Cyanidin-3-glucoside significantly inhibited ATP-induced mitochondrial depolarization. The intracellular Ca(2+) chelator BAPTA-AM or the mitochondrial Ca(2+) uniporter inhibitor RU360 blocked the ATP-induced mitochondrial depolarization in the presence of cyanidin-3-glucoside. Cyanidin-3-glucoside blocked ATP-induced formation of ROS. BAPTA-AM further decreased the formation of ROS in the presence of cyanidin-3-glucoside. All these results suggest that cyanidin-3-glucoside inhibits ATP-induced calcium signaling in PC12 cells by inhibiting multiple pathways which are the influx of extracellular Ca(2+) through the nimodipine and ω-conotoxin-sensitive and -insensitive pathways and the release of Ca(2+) from intracellular stores. In addition, cyanidin-3-glucoside inhibits ATP-induced formation of ROS by inhibiting Ca(2+)-induced mitochondrial depolarization.

Effects of grape seed proanthocyanidin extract on pentylenetetrazole-induced kindling and associated cognitive impairment in rats

Numerous studies have demonstrated the antioxidant effects of grape seed proanthocyanidin extract (GSPE). The generation of free radicals and the ensuing apoptosis may contribute to the pathogenesis of epilepsy; therefore, in the present study, we examined the effects of GSPE on cognitive impairment and neuronal damage induced by chronic seizures in rats. Seizures were induced by a daily intraperitoneal (i.p.) injection of pentylenetetrazole (PTZ; 35 mg/kg/day, 36 days). Two other groups were treated with GSPE (100 or 200 mg/kg/day, orally) for 24 days and then for 36 days prior to each PTZ injection. After the final PTZ injection, hippocampus-dependent spatial learning was assessed using the Morris water maze (MWM). The rats were then sacrificed for the measurement of hippocampal malondialdehyde (MDA, a measure of lipid peroxidation) and glutathione (GSH, a measure of endogenous antioxidant capacity) levels, and for the expression of pro-apoptotic factors [cytochrome c (Cyt c), caspase‑9 and caspase‑3]. The mitochondrial generation of reactive oxygen species (ROS), degree of mitochondrial swelling, neuronal damage and mitochondrial ultrastructure were also examined. Performance in the MWM was markedly impaired by PTZ-induced seizures, as evidenced by longer escape latencies during training and fewer platform crossings during the probe trial. This cognitive decline was accompanied by oxidative stress (MDA accumulation, ROS generation, reduced GSH activity), an increased expression of pro-apoptotic proteins, as well as damage to CA1 pyramidal neurons and the mitochondria. Pre-treatment with GSPE dose‑dependently reversed PTZ-induced impaired performance in the MWM, oxidative stress, mitochondrial ROS generation, the expression of pro-apoptotic proteins and neuronal and mitochondrial damage. Thus, GSPE may reverse the hippocampal dysfunction induced by chronic seizures, by reducing oxidative stress and preserving mitochondrial function.

Calcium dysregulation and neuroinflammation: discrete and integrated mechanisms for age-related synaptic dysfunction

Some of the best biomarkers of age-related cognitive decline are closely linked to synaptic function and plasticity. This review highlights several age-related synaptic alterations as they relate to Ca(2+) dyshomeostasis, through elevation of intracellular Ca(2+), and neuroinflammation, through production of pro-inflammatory cytokines including interleukin-1 beta (IL-1β) and tumor necrosis factor-alpha (TNF-α). Though distinct in many ways, Ca(2+) and neuroinflammatory signaling mechanisms exhibit extensive cross-talk and bidirectional interactions. For instance, cytokine production in glial cells is strongly dependent on the Ca(2+) dependent protein phosphatase calcineurin, which shows elevated activity in animal models of aging and disease. In turn, pro-inflammatory cytokines, such as TNF, can augment the expression/activity of L-type voltage sensitive Ca(2+) channels in neurons, leading to Ca(2+) dysregulation, hyperactive calcineurin activity, and synaptic depression. Thus, in addition to discussing unique contributions of Ca(2+) dyshomeostasis and neuroinflammation, this review emphasizes how these processes interact to hasten age-related synaptic changes.

Improvement in Memory and Brain Long-term Potentiation Deficits Due to Permanent Hypoperfusion/Ischemia by Grape Seed Extract in Rats

OBJECTIVE(S)

Cerebral hypoperfusion/ischemia (CHI) is a neurological disease where impaired hippocampus electrical activity and cognition caused by a serial pathophysiological events. This study aimed to evaluate the effects of chronic oral administration of grape seed extract (GSE) on passive avoidance memory and long-term potentiation (LTP) after permanent bilateral common carotid arteries occlusion (2CCAO) in male adult rats.

MATERIALS AND METHODS

Thirty-two adult male Wistar rats were randomly divided into: 1) Sham+Veh, 2) Isch+Veh, 3) Sham+GSE, 4) Isch+GSE. In order to make 2CCAO as an animal model of CHI, carotid arteries were ligatured and then cut bilaterally. To evaluation of passive avoidance memory, step-down latency (STL) was measured and LTP was recorded from hippocampal dentate gyrus (DG) after high frequency stimulation (HFS) in all rats.

RESULTS

We found that memory was significantly impaired in rats after CHI (P<0.001) concomitant with hippocampal LTP inhibition (P<0.05, P<0.01 for LTP1 and LTP48 respectively). GSE treatment significantly improved memory impairment and increased hippocampal LTP in rats with 2CCAO.

CONCLUSION

Our results in present study suggest that GSE exhibits therapeutic potential for short-and long-term memories as well as LTP in DG, which is most likely related at least in part to its antioxidative and free radical scavenging actions.

Inhibitory effects of acorn extract on glutamate-induced calcium signaling in cultured rat hippocampal neurons

Various effects of acorn extract have been reported including antioxidant activity, cytotoxicity against cancer cells, and the levels of acetylcholine and its related enzyme activities in the dementia mouse models. However, it is unclear whether acorn extract inhibits glutamate-induced calcium signaling in hippocampal neurons. This study was an investigation into the effect of acorn extract on intracellular free Ca concentrations ([Ca]) in cultured rat hippocampal neurons using fura-2-based digital calcium imaging and photometry. Hippocampal neurons were used between 10 and 14 d in culture from embryonic day-18 rats. Treatment with acorn extract (1 µg/mL to 1 mg/mL) for 30 min inhibited glutamate (100 µM)-induced [Ca] increases in a dose-dependent manner (IC=46.9 µg/mL). After depletion of intracellular Ca stores by treatment with the inhibitor endoplasmic reticulum Ca-ATPase, thapsigargin (1 µM), treatment with acorn extract (50 µg/mL) for 30 min decreased the subsequent glutamate-induced [Ca] increases. Acorn extract significantly inhibited (S)-alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) (30 µM)-induced [Ca] increases. In addition, acorn extract inhibited the AMPA-induced [Ca] responses in the presence of 1 µM nimodipine. Acorn extract also significantly inhibited N-methyl-D-aspartate (100 µM)-induced [Ca] increases. Acorn extract significantly inhibited 50 mM KCl -induced [Ca] increases. Acorn extract significantly inhibited (S)-3,5-dihydroxyphenylglycine-induced [Ca] responses. Moreover, acorn extract almost completely blocked synaptically mediated [Ca] spikes induced by decreasing extracellular Mg concentration to 0.1 mM. These results suggest that acorn extract inhibits synaptically induced frequent [Ca] spikes through multiple pathways such as ionotropic glutamate receptors, voltage-gated Ca channels and metabotropic glutamate receptors in cultured rat hippocampal neurons.

Chemical analysis and effect of blueberry and lingonberry fruits and leaves against glutamate-mediated excitotoxicity

Phenolic compounds are a large class of phytochemicals that are widespread in the plant kingdom and known to have antioxidant capacities. This study aimed to determine the antioxidant capacities as well as the content of total soluble phenolics, anthocyanins, tannins, and flavonoids in the fruits and leaves of blueberries and lingonberries growing in Newfoundland. This study also determined the potential neuroprotective effect of extracts from fruits and leaves against glutamate-mediated excitotoxicity, which is believed to contribute to disorders such as stroke and neurodegenerative diseases. Lingonberry and blueberry plants were found to be rich sources of phenolic compounds. Total antioxidant capacities in terms of radical scavenging activity and reducing power were much higher in leaves of both plants as compared to their fruits. These results were in correlation with phenolic contents including total flavonoids, anthocyanins, and tannins. Brain-derived cell cultures from rats were prepared and grown for about 2 weeks. Cell cultures were treated with glutamate (100 μM) for 24 h, and the effect of extracts was determined on cells subjected to this excitotoxicity. Glutamate treatment caused approximately 23% cell loss when measured after 24 h of exposure. Whereas lingonberry fruit extract did not provide protection from glutamate toxicity, blueberry fruit extracts were extremely protective. Leaf extracts of both lingonberry and blueberry showed a significant neuroprotective effect. The greater protective effect of leaf extracts was in correlation with the levels of phenolics and antioxidant capacity. These findings suggest that berries or their components may contribute to protecting the brain from various pathologies.

(1)H NMR-based metabolomics exploring biomarkers in rat cerebrospinal fluid after cerebral ischemia/reperfusion

In our study, metabolomics was used to investigate biochemical changes in the early stages of rats focal cerebral ischemia/reperfusion (I/R) injury. Cerebrospinal fluid (CSF) samples at 0, 0.5, 1, 3, and 6 h of reperfusion (n = 10), based on (1)H NMR spectroscopy and multivariate data analyses, were tested to analyze the changing of metabolites during the early disease process. Partial least squares-discriminant analysis scores plots of the (1)H NMR data revealed clear differences among the experiment groups. Combining the results of the loading plot and t-test, we found that twenty-seven metabolites were changed significantly (p < 0.05) in the CSF samples among the different groups. Among that, the potential biomarkers in CSF of ischemic rats were: acetic acid, 3-hydroxyisovaleric acid, 3-hydroxybutyric acid, choline, l-alanine, creatine, creatinine, glycine, pyruvic acid, glycerol, glutamic acid, d-fructose, l-lactic acid and acetone. These findings help us understand the biochemical metabolite changes in CSF of I/R rats in early stages. What's more, metabolomics may, therefore, have the potential to be developed into a clinically useful diagnostic tool of ischemic brain injury.

Fluoxetine suppresses synaptically induced [Ca²⁺]i spikes and excitotoxicity in cultured rat hippocampal neurons

Fluoxetine is a widely used antidepressant with an action that is primarily attributed to the inhibition of serotonin re-uptake into the synaptic terminals of the central nervous system. Fluoxetine also has blocking effects on various ion channels, including Ca(2+) channels. It remains unclear, however, how fluoxetine may affect synaptically induced [Ca(2+)](i) spikes. We investigated the effects of fluoxetine on [Ca(2+)](i) spikes, along with the subsequent neurotoxicity that is synaptically evoked by lowering extracellular Mg(2+) in cultured rat hippocampal neurons. Fluoxetine inhibited the synaptically induced [Ca(2+)](i) spikes in p-chloroamphetamine-treated and non-treated neurons, in a concentration-dependent manner. However, other selective serotonin reuptake inhibitors, such as paroxetine and citalopram, did not significantly affect the spikes. Pretreatment with fluoxetine for 5 min inhibited [Ca(2+)](i) increases induced by glutamate, α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid, and N-methyl-d-aspartate. Fluoxetine also inhibited α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid-induced currents. In addition, fluoxetine decreased the [Ca(2+)](i) responses induced by the metabotrophic glutamate receptor agonist (S)-3,5-dihydroxyphenylglycine or the ryanodine receptor agonist caffeine. Fluoxetine inhibited [Ca(2+)](i) responses induced by 20mM KCl. Fluoxetine decreased the release of FM1-43 induced by electric field stimulation. Furthermore, fluoxetine inhibited 0.1mM [Mg(2+)](o)-induced cell death. Collectively, our results suggest that fluoxetine suppresses the spikes and protects neurons against excitotoxicity, particularly in cultured rat hippocampal neurons, presumably due to both direct inhibition of presynaptic glutamate release and postsynaptic glutamate receptor-mediated [Ca(2+)](i) signaling. In addition to an indirect inhibitory effect via 5-HT levels, these data suggest a new, possibly direct inhibitory action of fluoxetine on synaptically induced [Ca(2+)](i) spikes and neuronal cell death.