Valproic acid attenuates ischemia-reperfusion injury in the rat brain through inhibition of oxidative stress and inflammation

Panobinostat, a Histone Deacetylase Inhibitor, Reduces LPS-Induced Expression of Inducible Nitric Oxide Synthase in Rat Immortalized Microglia HAPI Cells

Microglia, resident immune cells in the central nervous system (CNS), play a critical role in maintaining CNS homeostasis. However, microglia activated in response to brain injury produce various inflammatory mediators, including nitric oxide (NO) and proinflammatory cytokines, leading to considerable neuronal damage. NO generated by inducible NO synthase (iNOS) rapidly reacts with superoxide to form a highly toxic product, peroxynitrite. Therefore, iNOS is considered to be a putative therapeutic target for cerebral ischemia. Here, we examined the effects of panobinostat (Pano), a histone deacetylase inhibitor, on lipopolysaccharide (LPS)-induced iNOS expression using rat immortalized microglia HAPI cells. Pano inhibited LPS-induced expression of iNOS mRNA and NO production in a dose-dependent manner; however, it had little effect on the LPS-induced activation of c-Jun N-terminal kinase (JNK) and p38 or nuclear translocation of nuclear factor-κB (NF-κB). The interferon-β (IFN-β)/signal transducer and activator of transcription (STAT) pathway is essential for LPS-induced iNOS expression in macrophages/microglia. We also examined the effects of Pano on LPS-induced IFN-β signaling. Pano markedly inhibited LPS-induced IFN-β expression and subsequent tyrosine phosphorylation of STAT1. However, the addition of IFN-β restored the decreased STAT1 phosphorylation but not the decreased iNOS expression. In addition, Pano inhibited the LPS-increased expression of octamer binding protein-2 and interferon regulatory factor 9 responsible for iNOS expression, but IFN-β addition also failed to restore the decreased expression of these factors. Thus, we conclude that the inhibitory effects of Pano are due not only to the inhibition of the IFN-β/STAT axis but also to the downregulation of other factors not involved in this axis.

Neuroprotective strategies for neonatal hypoxic-ischemic brain damage: Current status and challenges

Neonatal hypoxic-ischemic brain damage (HIBD) is a prominent contributor to both immediate mortality and long-term impairment in newborns. The elusive nature of the underlying mechanisms responsible for neonatal HIBD presents a significant obstacle in the effective clinical application of numerous pharmaceutical interventions. This comprehensive review aims to concentrate on the potential neuroprotective agents that have demonstrated efficacy in addressing various pathogenic factors associated with neonatal HIBD, encompassing oxidative stress, calcium overload, mitochondrial dysfunction, endoplasmic reticulum stress, inflammatory response, and apoptosis. In this review, we conducted an analysis of the precise molecular pathways by which these drugs elicit neuroprotective effects in animal models of neonatal hypoxic-ischemic brain injury (HIBD). Our objective was to provide a comprehensive overview of potential neuroprotective agents for the treatment of neonatal HIBD in animal experiments, with the ultimate goal of enhancing the feasibility of clinical translation and establishing a solid theoretical foundation for the clinical management of neonatal HIBD.

Transient plasticity response is regulated by histone deacetylase inhibitor in oxygen-glucose deprivation condition

BACKGROUND

The pathological form of synaptic plasticity, ischemic long-term potentiation (iLTP), induced by oxygen and glucose deprivation (OGD), is implicated in the acute phase of stroke with the potentiation of N-methyl-D-aspartate receptor (NMDAR). While there has been widespread attention on the excitatory system, a recent study reported that γ-aminobutyric acid (GABA)ergic system is also involved in iLTP. Valproic acid (VPA), a histone deacetylase inhibitor, protects against ischemic damage. However, whether VPA regulates early phase plasticity in ischemic stroke remains unknown. The present study aims to investigate the potential role and mechanism of VPA in ischemic stroke.

METHODS

A brief exposure of OGD on the hippocampal slices and the induction of photothrombotic ischemia (PTI) were used as ex vivo and in vivo models of ischemic stroke, respectively.

RESULTS

Using extracellular recordings, iLTP was induced in the hippocampal Schaffer collateral pathway following OGD exposure. VPA treatment abolished hippocampal iLTP via GABAA receptor enhancement and extracellular signal-regulated kinase (ERK) phosphorylation. Administration of VPA reduced brain infarct volume and motor dysfunction in mice with PTI. Moreover, VPA protected against ischemic injury by upregulating the GABAergic system and ERK phosphorylation, as well as by reducing of matrix metalloproteinase in a PTI-induced ischemic stroke model.

CONCLUSIONS

Together, this study revealed the protection of VPA in ex vivo OGD-induced pathological form of neuroplasticity and in vivo PTI-induced brain damage and motor dysfunction through rescuing GABAergic deficiency and the pathological hallmarks of ischemia.

Therapeutic Administration of Oxcarbazepine Saves Cerebellar Purkinje Cells from Ischemia and Reperfusion Injury Induced by Cardiac Arrest through Attenuation of Oxidative Stress

Research reports using animal models of ischemic insults have demonstrated that oxcarbazepine (a carbamazepine analog: one of the anticonvulsant compounds) extends neuroprotective effects against cerebral or forebrain injury induced by ischemia and reperfusion. However, research on protective effects against ischemia and reperfusion cerebellar injury induced by cardiac arrest (CA) and the return of spontaneous circulation has been poor. Rats were assigned to four groups as follows: (Groups 1 and 2) sham asphyxial CA and vehicle- or oxcarbazepine-treated, and (Groups 3 and 4) CA and vehicle- or oxcarbazepine-treated. Vehicle (0.3% dimethyl sulfoxide/saline) or oxcarbazepine (200 mg/kg) was administered intravenously ten minutes after the return of spontaneous circulation. In this study, CA was induced by asphyxia using vecuronium bromide (2 mg/kg). We conducted immunohistochemistry for calbindin D-28kDa and Fluoro-Jade B histofluorescence to examine Purkinje cell death induced by CA. In addition, immunohistochemistry for 4-hydroxy-2-nonenal (4HNE) was carried out to investigate CA-induced oxidative stress, and immunohistochemistry for Cu, Zn-superoxide dismutase (SOD1) and Mn-superoxide dismutase (SOD2) was performed to examine changes in endogenous antioxidant enzymes. Oxcarbazepine treatment after CA significantly increased the survival rate and improved neurological deficit when compared with vehicle-treated rats with CA (survival rates ≥ 63.6 versus 6.5%), showing that oxcarbazepine treatment dramatically protected cerebellar Purkinje cells from ischemia and reperfusion injury induced by CA. The salvation of the Purkinje cells from ischemic injury by oxcarbazepine treatment paralleled a dramatic reduction in 4HNE (an end-product of lipid peroxidation) and increased or maintained the endogenous antioxidant enzymes (SOD1 and SOD2). In brief, this study shows that therapeutic treatment with oxcarbazepine after CA apparently saved cerebellar neurons (Purkinje cells) from CA-induced neuronal death by attenuating oxidative stress and suggests that oxcarbazepine can be utilized as a therapeutic medicine for ischemia and reperfusion brain (cerebellar) injury induced by CA.

Betaine Ameliorates Brain Damage in a Rat Model of Ischemia/Reperfusion Injury

Brain ischemia and reperfusion (I/R) injury may lead to a poor prognosis for ischemic stroke, which could be alleviated by anti-oxidants with diminished oxidative stress. Betaine is a natural nutrient found in beetroot and seafood to improve cognitive performance in the elderly. The present study investigated whether betaine could protect the brain from I/R injury. Results showed that betaine treatment could reduce H₂O₂-induced cell death in the PC12 cell line. Pretreatment with betaine reduced the brain infarct volume and neuronal apoptosis in a rat I/R injury model induced by two-hour middle cerebral artery occlusion (MCAO). Biochemical analyses indicated that betaine treatment decreased pro-inflammatory cytokine production and reduced oxidative stress after I/R injury. Betaine increased the expression of anti-oxidative enzymes, such as glutathione peroxidase 4 (Gpx4) and superoxide dismutase 1 (Sod1), and anti-oxidative non-enzymatic genes, such as 3-mercaptopyruvate sulfurtransferase (Mpst), methionine sulfoxide reductases b1 (Msrb1), and Msrb2. These data suggest that betaine exerts a neuroprotective effect in I/R injury through enzymatic and non-enzymatic anti-oxidative systems and anti-inflammatory mechanisms.

The effect of antiepileptic drugs on re-myelinization of axons: Phenytoin, levetiracetam, carbamazepine, and valproic acid, used following traumatic brain injury

OBJECTIVE

Traumatic brain injury is a major health and socioeconomic problem and the first cause of young death worldwide. For this reason, the prevention of post-traumatic brain injury and the research of new methods for it are important today. In this study, we aimed to determine whether the use of antiepileptic drugs contributed to axonal healing after traumatic brain injury.

METHODS

Thirty-six Long-Evans rats, each weighing 300-350 g, were used in this study. A total of 6 groups, including the sham, control, and 4 study groups, were determined. A 1.5 mm-sized trauma was created in the biparietal area with a blunt-tipped dissector. Carbamazepine phenytoin valproic acid and levetiracetam (phenytoin: 30 mg/kg, valproic acid: 60 mg/kg, levetiracetam: 80 mg/kg, and carbamazepine: 36 mg/kg) were intraperitoneally administered to the study groups, and the control group intraperitoneally received a physiological saline solution (15 ml/kg) twice daily for 3 days. After 72 h, hemispheres of the sacrificed subjects were taken for examination in biochemistry and histology. Glutathione, malondialdehyde, and NG2 levels in the samples were determined.

RESULTS

No significant difference was found in biochemical measurements. Histopathological examination revealed that the NG2 expression was more intense in the group treated with phenytoin and levetiracetam (phenytoin was partly higher) and the amount of edema decreased. The NG2 expression increased and the edema decreased, though lower in the group treated with carbamazepine and valproic acid, compared with phenytoin and levetiracetam. An increase in the NG2 expression and edema intensity were determined in the control and sham groups.

CONCLUSION

Antiepileptic drug selection after traumatic brain injury is an important medical matter. Although the patient-oriented selection is essential, the study suggests that the choice of phenytoin, levetiracetam carbamazepine, and valproic acid will, respectively, have an accelerating effect for axonal healing.

Pretreatment with valproic acid alleviates pulmonary fibrosis through epithelial-mesenchymal transition inhibition in vitro and in vivo

Epithelial-mesenchymal transition (EMT) plays a crucial role in the development of pulmonary fibrosis. This study aims to investigate the effects of valproic acid (VPA) on EMT in vitro and in vivo. In vitro, EMT was induced by the administration of transforming growth factor-β1 (TGF-β1) in a human alveolar epithelial cell line (A549). The dose effects of VPA (0.1-3 mM) on EMT were subsequently evaluated at different timepoints. VPA (1 mM) was applied prior to the administration of TGF-β1 and the expression of E-cadherin, vimentin, p-Smad2/3 and p-Akt was assessed. In addition, the effects of a TGF-β type I receptor inhibitor (A8301) and PI3K-Akt inhibitor (LY294002) on EMT were evaluated. In vivo, the effects of VPA on bleomycin-induced lung fibrosis were evaluated by assessing variables such as survival rate, body weight and histopathological changes, whilst the expression of E-cadherin and vimentin in lung tissue was also evaluated. A8301 and LY294002 were used to ascertain the cellular signaling pathways involved in this model. The administration of VPA prior to TGF-β1 in A549 cells prevented EMT in both a time- and concentration-dependent manner. Pretreatment with VPA downregulated the expression of both p-Smad2/3 and p-Akt. A8301 administration increased the expression of E-cadherin and reduced the expression of vimentin. LY294002 inhibited Akt phosphorylation induced by TGF-β1 but failed to prevent EMT. Pretreatment with VPA both increased the survival rate and prevented the loss of body weight in mice with pulmonary fibrosis. Interestingly, both VPA and A8301 prevented EMT and facilitated an improvement in lung structure. Overall, pretreatment with VPA attenuated the development of pulmonary fibrosis by inhibiting EMT in mice, which was associated with Smad2/3 deactivation but without Akt cellular signal involvement.

Dexmedetomidine inhibits inflammatory response and oxidative stress through regulating miR-205-5p by targeting HMGB1 in cerebral ischemic/reperfusion

OBJECTIVE

To investigate effects of dexmedetomidine (DEX) on miR-205-5p/HMGB1 axis in cerebral ischemic/reperfusion (I/R) injury.

METHODS

Both in vivo I/R rat model and in vitro hypoxia/reoxygenation (H/R) cell model using rat hippocampal neurons cells were established. miR-205-5p was overexpressed or inhibited by transfection of miR-205-5p mimics or inhibitor. HMGB1 was overexpressed by transfection overexpression plasmids (OE-HMGB1). TTC staining was used for measurement of infraction volume. Oxidative stress was evaluated by measurement of reactive oxygen species (ROS), malondialdehyde (MDA) and superoxide dismutase (SOD) and inflammation was evaluated by measurement of IL-1β, IL-6 and TNF-α. Dual luciferase reporter assay was performed to confirm binding between miR-205-5p and HMGB1. The expression levels of miR-205-5p, and HMGB1 were measured using RT-qPCR. Western blotting was used to test the protein expression levels of HMGB1, nuclear factor erythroid 2-related factor 2 (Nrf2), glutathione peroxidase (GPx), glutathione reductase (GR), heme oxygenase 1 (HO-1) and catalase (CAT).

RESULTS

Treatment of DEX significantly reduced brain infraction volume, decreased Longa's neurological function score and inhibited oxidative stress and inflammation in brain tissues of I/R rats, which were all reversed by inhibition of miR-205-5p. Both treatment of DEX or overexpression of miR-205-5p restricted oxidative stress and inflammation in H/R rat hippocampal neurons cells. The inhibition of miR-205-5p reversed the effects of DEX, while the overexpression of HMGB1 reversed the effects of miR-205-5p overexpression in H/R rat hippocampal neurons cells. Dual luciferase reporter assay showed miR-205-5p directly targeted HMGB1.

CONCLUSION

DEX improved I/R injury by suppressing brain oxidative stress and inflammation DEX improved I/R injury by suppressing brain oxidative stress and inflammation through activating miR-205-5p/HMGB1 axis through activating miR-205-5p/HMGB1 axis.

Post-stroke Delivery of Valproic Acid Promotes Functional Recovery and Differentially Modifies Responses of Peri-Infarct Microglia

The specific role of peri-infarct microglia and the timing of its morphological changes following ischemic stroke are not well understood. Valproic acid (VPA) can protect against ischemic damage and promote recovery. In this study, we first determined whether a single dose of VPA after stroke could decrease infarction area or improve functional recovery. Next, we investigated the number and morphological characteristic of peri-infarct microglia at different time points and elucidated the mechanism of microglial response by VPA treatment. Male Sprague-Dawley rats were subjected to distal middle cerebral artery occlusion (dMCAo) for 90 min, followed by reperfusion. Some received a single injection of VPA (200 mg/kg) 90 min after the induction of ischemia, while vehicle-treated animals underwent the same procedure with physiological saline. Infarction volume was calculated at 48 h after reperfusion, and neurological symptoms were evaluated. VPA didn’t significantly reduce infarct volume but did ameliorate neurological deficit at least partially compared with vehicle. Meanwhile, VPA reduced dMCAo-induced elevation of IL-6 at 24 h post-stroke and significantly decreased the number of CD11b-positive microglia within peri-infarct cortex at 7 days. Morphological analysis revealed that VPA therapy leads to higher fractal dimensions, smaller soma size and lower circularity index of CD11b-positive cells within peri-infarct cortex at both 2 and 7 days, suggesting that VPA has core effects on microglial morphology. The modulation of microglia morphology caused by VPA might involve HDAC inhibition-mediated suppression of galectin-3 production. Furthermore, qPCR analysis of CD11b-positive cells at 3 days post-stroke suggested that VPA could partially enhance M2 subset polarization of microglia in peri-infarct cortex. Analysis of VPA-induced changes to gene expressions at 3 days post-stroke implies that these alternations of the biomarkers and microglial responses are implicated in the upregulation of wound healing, collagen trimmer, and extracellular matrix genes within peri-infarct cortex. Our results are the first to show that a low dose of VPA promotes short-term functional recovery but does not alter infarct volume. The decreases in the expression of both IL-6 and galectin-3 might influence the morphological characteristics and transcriptional profiles of microglia and extracellular matrix remodeling, which could contribute to the improved recovery.

Suppression of Oxidative Stress as Potential Therapeutic Approach for Normal Tension Glaucoma

Glaucoma is a neurodegenerative disease of the eye, which involves degeneration of retinal ganglion cells (RGCs): the output neurons of the retina to the brain, which with their axons comprise the optic nerve. Recent studies have shown the possible involvement of oxidative stress in the pathogenesis of glaucoma, especially in the subtype of normal tension glaucoma. Basic experiments utilizing rodent and primate models of glaucoma revealed that antioxidants protect RGCs under various pathological conditions including glutamate neurotoxicity and optic nerve injury. These results suggested that existing drugs and food factors may be useful for prevention and hence therapy of glaucoma. In this review, we highlight some therapeutic candidates, particularly those with antioxidant properties, and discuss the therapeutic potential of RGC protection by modulating gene expressions that prevent and ameliorate glaucoma.

Valproate improves middle cerebral artery occlusion-induced ischemic cerebral disorders in mice and oxygen-glucose deprivation-induced injuries in microglia by modulating RMRP/PI3K/Akt axis

Valproate (VPA) is capable of attenuating ischemic stroke (IS)-related disorders in brain tissues. Long non-coding RNAs (lncRNAs) are involved in the progression of IS. In the current study, the role of lncRNA RMRP in the protective effects of VPA against IS was explored. Mice were subjected to middle cerebral artery occlusion (MCAO) model to induce IS injures and then were administrated with VPA. The effects of VPA on infarction area and apoptosis in brain tissues, and the RMRP-regulated PI3K/Akt signaling activity were detected. Thereafter, oxygen-glucose deprivation (OGD) BV-2 cells were used as the in vitro model to further explore the mechanism underlying VPA function. The administration of VPA reduced infarction area and suppressed apoptosis in brain tissues of MCAO mice. VPA also inhibited RMRP expression and activated PI3K/Akt signaling. In OGD BV-2 cells, the treatment of VPA increased viability and attenuated apoptosis, which was associated with the inhibition of RMRP and the activation of PI3K/Akt pathway. Moreover, the induced expression of RMRP blocked the anti-OGD function of VPA, indicating the key role of RMRP inhibition in the effects of VPA on nerve system. Collectively, VPA attenuated MCAO/OGD-induced disorders in mice and microglia. The effects were dependent on the inhibition of RMRP, which subsequently induced the activation of PI3K/Akt signaling.

Effects of Diclofenac Versus Meloxicam in Pentylenetetrazol-Kindled Mice

Epilepsy comes after stroke as the most common chronic neurological disorder worldwide. Inflammation enhances neuronal hyperexcitability that could provide a background setting for the development of epilepsy. The aim of this study was to assess the effect of valproate (VAL), diclofenac (DIC), meloxicam (MEL), VAL + MEL and VAL + DIC in pentylenetetrazol (PTZ) kindled mice. Seventy mice were randomly allocated into 7 equal groups; Control, PTZ, VAL, DIC, MEL, VAL + MEL and VAL + DIC groups. Kindling was induced by PTZ (40 mg/kg, i.p.) injection every other day for 17 days. The drugs were administered, 30 min before each PTZ injection till the end of the schedule. Seizure score, latency, duration and mortality rate were recorded in all groups. Tumor necrosis factor- α (TNF-α), interleukin-1β (IL-1β), malondialdehyde (MDA) and prostaglandin E2 (PGE2) levels as well as reduced glutathione (GSH) content were assessed in brain homogenate at the end of the schedule. VAL, DIC, MEL, VAL + MEL and VAL + DIC decreased seizure score and duration. Meanwhile, they increased the latency period. PTZ increased TNF-α, IL-1β, MDA, and PGE2 levels meanwhile, it decreased GSH content. Administration of VAL, DIC, MEL, VAL + MEL and VAL + DIC decreased TNF-α, IL-1β, MDA, and PGE2 levels meanwhile, they increased GSH content in the brain homogenates. Effects of VAL + DIC combination on the studied parameters were significant in relation to VAL. VAL, DIC, MEL, VAL + MEL and VAL + DIC produced anticonvulsant effect and mitigated inflammation and oxidative stress in PTZ-kindled mice. Interestingly, DIC rather than MEL enhanced the anticonvulsant effect VAL.

The novel mechanism of valproate to prevent peritoneal adhesion formation

PURPOSE

A novel pharmacological mechanism of valproate was analyzed using a hamster model of adhesion.

METHODS

Valproate or placebo was administered just after cecal injury and adhesion severity scores and histological were analyzed.

RESULTS

The adhesion severity scores in the placebo- and valproate-treated groups were 2.67 ± 0.42 and 1.0 ± 0.37, respectively, with a significant difference between the groups. A significant increase in mast cell numbers was observed in the placebo-treated group vs. the sham-operated group; however, the mast cell number in the adhesive lesion was significantly lower in the valproate-treated group than in the placebo-treated group. The number of cells positive for chymase, an enzyme in mast cells, in the adhesive lesion was significantly higher in the placebo-treated group, but its increase was attenuated significantly by treatment with valproate. The myeloperoxidase gene expression level in the cecum was significantly higher in the placebo-treated group than in the sham-operated group, but there was no significant difference in the myeloperoxidase gene expression level between the sham-operated and valproate-treated groups in. In an in vitro experiment, valproate inhibited purified human and hamster chymases dose-dependently.

CONCLUSION

The chymase inhibitory effect of valproate may contribute to prevent adhesion formation after abdominal injury.

Total Glycosides of Cistanche deserticola Promote Neurological Function Recovery by Inducing Neurovascular Regeneration via Nrf-2/Keap-1 Pathway in MCAO/R Rats

Background

The traditional Chinese medicine Cistanche deserticola has been reported to be valid for cardiovascular and cerebrovascular diseases. However, its active components for the protection of ischemic stroke are not clear. We aimed to explore the active components of C. deserticola against ischemic stroke as well as its potential mechanisms.

Methods

We investigated the brain protective effects of extracts from C. deserticola, total glycosides (TGs), polysaccharides (PSs), and oligosaccharides (OSs) in a rat model of middle cerebral artery occlusion-reperfusion (MCAO/R). 2, 3, 5-Triphenyltetrazolium chloride (TTC) staining was used to assess the cerebral infarction volume, and Evans blue assay was adopted to assess the blood-brain barrier (BBB) permeability. Then, the expressions CD31, α-SMA, PDGFRβ, SYN, PSD95, MAP-2, ZO-1, claudin-5, occludin, Keap-1, and Nrf-2 were analyzed using western blotting or immunofluorescence, and the activities MDA, SOD, CAT, and GSH-Px were analyzed using kits.

Results

TGs treatment remarkably decreased neurological deficit scores and infarction volumes, promoted angiogenesis and neural remodeling, and effectively maintained blood-brain-barrier integrity compared with the model group. Furthermore, TGs significantly decreased MDA levels and increased antioxidant activities (SOD, CAT, and GSH-Px) in brains. Meanwhile, TGs remarkably downregulated Keap-1 expression and facilitated Nrf-2 nuclear translocation. On the contrary, no protective effects were observed for PSs and OSs groups.

Conclusion

TGs are the main active components of C. deserticola against MCAO/R-induced cerebral injury, and protection is mainly via the Nrf-2/Keap-1 pathway.

Modeling poststroke epilepsy and preclinical development of drugs for poststroke epilepsy

Stroke is a severe clinical issue for global public health, representing the third leading cause of death and a major cause of disability in developed countries. Progresses in the pharmacological treatment of the acute stroke have given rise to a significant decrease in its mortality rate. However, as a result, there has been an increasing number of stroke survivors living with disability worldwide. Poststroke epilepsy (PSE) is a common clinical complication following stroke. Seizures can arise in close temporal association with stroke damage and/or after a variably longer interval. Overall, PSE have a good prognosis; in fact, its responding rate to antiepileptic drugs (AEDs) is higher than other types of epilepsy. However, regarding pharmacological treatment, some issues are still unresolved. To this aim, a deeper understanding of mechanisms underlying the transformation of infarcted tissue into an epileptic focus or better from a nonepileptic brain to an epileptic brain is also mandatory for PSE. However, studying epileptogenesis in patients with PSE clearly has several limitations and difficulties; therefore, modeling PSE is crucial. Until now, different experimental models have been used to study the etiopathology of cerebrovascular stroke with or without infarction, but few studies focused on poststroke epileptogenesis and PSE. In this review, we show a brief overview on the features emerging from preclinical research into experimental PSE, which could affect the discovery of biomarkers and therapy strategies for poststroke epileptogenesis. This article is part of the Special Issue "Seizures & Stroke".

Post-treatment with oxcarbazepine confers potent neuroprotection against transient global cerebral ischemic injury by activating Nrf2 defense pathway

Oxcarbazepine (OXC), a voltage-gated sodium channel blocker, is an antiepileptic medication and used for the bipolar disorders treatment. Some voltage-gated sodium channel blockers have been demonstrated to display strong neuroprotective properties in models of cerebral ischemia. However, neuroprotective effects and mechanisms of OXC have not yet been reported. Here, we investigated the protective effect of OXC and its mechanisms in the cornu ammonis 1 subfield (CA1) of gerbils subjected to 5 min of transient global cerebral ischemia (tGCI). tGCI led to death of most pyramidal neurons in CA1 at 5 days after ischemia. OXC (100 and 200 mg/kg) was intraperitoneally administered once at 30 min after tGCI. Treatment with 200 mg/kg, not 100 mg/kg OXC, significantly protected CA1 pyramidal neurons from tGCI-induced injury. OXC treatment significantly decreased superoxide anion production, 4-hydroxy-2-nonenal and 8-hydroxyguanine levels in ischemic CA1 pyramidal neurons. In addition, the treatment restored levels of superoxide dismutases, catalase, and glutathione peroxidase. Furthermore, the treatment distinctly inhibited tGCI-induced microglia activation and significantly reduced levels of pro-inflammatory cytokines (interleukin-1β and tumor necrosis factor-α). In particular, OXC treatment significantly enhanced expressions of nuclear factor erythroid 2-related factor 2 (Nrf2) and its downstream protein heme oxygenase-1 in ischemic CA1. The neuroprotective effects of OXC were abolished by brusatol (an inhibitor of Nrf2). Taken together, these results indicate that post-treatment of OXC can display neuroprotection against brain injuries following ischemic insults. This neuroprotection may be displayed by attenuation of oxidative stress and neuroinflammation, which can be mediated by activation of Nrf2 pathway.

Expression and short-term prognostic value of miR-126 and miR-182 in patients with acute stroke

Expression and short-term prognostic value of miR-126 and miR-182 in patients with acute stroke were investigated. In total, 153 patients with acute stroke admitted to the Second Affiliated Hospital of Soochow University from February 2016 to February 2018 were enrolled into the observation group as group A [88 patients with acute cerebral infarction (AIS)] or group B [65 patients with cerebral hemorrhage (ICH)]. Furthermore, 69 healthy people receiving physical examinations in the hospital were enrolled into the control group. The relative expression of miR-126 and miR-182 in all subjects were measured and their correlation with the National Institute of Health stroke scale (NIHSS) and activities of daily living (ADL) scores was analyzed. After 3 months of follow-up, the correlation of miR-126 and miR-182 with the Modified Rankin Scale (MRS) score of patients was investigated. The receiver operating characteristic (ROC) curve was employed to explore the value of miR-126 and miR-182, alone or in combination, in predicting the prognosis of acute stroke patients. Subjects in the control group had markedly higher miR-126 expression and lower miR-182 expression than those in group A and group B in the observation group (P<0.05). Pearson's correlation analysis suggested a notable correlation of miR-126 and miR-182 with NIHSS and ADL scores. Patients with a mild condition or good prognosis had higher miR-126 expression and lower miR-182 expression than patients with a severe condition or poor prognosis (P<0.05). Both miR-126 and miR-182 predicted the prognosis of acute stroke, and the combination of miR-126 and miR-182 presented better accuracy. The expression levels of miR-126 and miR-182 are associated with the neurological function, self-care ability, and prognosis in patients with acute stroke is highly valuable for predicting the prognosis of patients.

The potential of drug repurposing combined with reperfusion therapy in cerebral ischemic stroke: A supplementary strategy to endovascular thrombectomy

Stroke is the major cause of adult disability and the second or third leading cause of death in developed countries. The treatment options for stroke (thrombolysis or thrombectomy) are restricted to a small subset of patients with acute ischemic stroke because of the limited time for an efficacious response and the strict criteria applied to minimize the risk of cerebral hemorrhage. Attempts to develop new treatments, such as neuroprotectants, for acute ischemic stroke have been costly and time-consuming and to date have yielded disappointing results. The repurposing approved drugs known to be relatively safe, such as statins and minocycline, may provide a less costly and more rapid alternative to new drug discovery in this clinical condition. Because adequate perfusion is thought to be vital for a neuroprotectant to be effective, endovascular thrombectomy (EVT) with advanced imaging modalities offers the possibility of documenting reperfusion in occluded large cerebral vessels. An examination of established medications that possess neuroprotective characters using in a large-vessel occlusive disorder with EVT may speed the identification of new and more broadly efficacious medications for the treatment of ischemic stroke. These approaches are highlighted in this review along with a critical assessment of drug repurposing combined with reperfusion therapy as a supplementary means for halting or mitigating stroke-induced brain damage.

Systematic review and meta-analysis of experimental studies evaluating the organ protective effects of histone deacetylase inhibitors

The clinical efficacy of organ protection interventions are limited by the redundancy of cellular activation mechanisms. Interventions that target epigenetic mechanisms overcome this by eliciting genome wide changes in transcription and signaling. We aimed to review preclinical studies evaluating the organ protection effects of histone deacetylase inhibitors (HDACi) with a view to informing the design of early phase clinical trials. A systematic literature search was performed. Methodological quality was assessed against prespecified criteria. The primary outcome was mortality, with secondary outcomes assessing mechanisms. Prespecified analyses evaluated the effects of likely moderators on heterogeneity. The analysis included 101 experimental studies in rodents (n = 92) and swine (n = 9), exposed to diverse injuries, including: ischemia (n = 72), infection (n = 7), and trauma (n = 22). There were a total of 448 comparisons due to the evaluation of multiple independent interventions within single studies. Sodium valproate (VPA) was the most commonly evaluated HDACi (50 studies, 203 comparisons). All of the studies were judged to have significant methodological limitations. HDACi reduced mortality in experimental models of organ injury (risk ratio = 0.52, 95% confidence interval 0.40-0.68, p < 0.001) without heterogeneity. HDACi administration resulted in myocardial, brain and kidney protection across diverse species and injuries that was attributable to increases in prosurvival cell signaling, and reductions in inflammation and programmed cell death. Heterogeneity in the analyses of secondary outcomes was explained by differences in species, type of injury, HDACi class (Class I better), drug (trichostatin better), and time of administration (at least 6 hours prior to injury better). These findings highlight a potential novel application for HDACi in clinical settings characterized by acute organ injury.

Immune Abnormalities in Autism Spectrum Disorder-Could They Hold Promise for Causative Treatment?

Autism spectrum disorders (ASD) are characterized by impairments in language and communication development, social behavior, and the occurrence of stereotypic patterns of behavior and interests. Despite substantial speculation about causes of ASD, its exact etiology remains unknown. Recent studies highlight a link between immune dysfunction and behavioral traits. Various immune anomalies, including humoral and cellular immunity along with abnormalities at the molecular level, have been reported. There is evidence of altered immune function both in cerebrospinal fluid and peripheral blood. Several studies hypothesize a role for neuroinflammation in ASD and are supported by brain tissue and cerebrospinal fluid analysis, as well as evidence of microglial activation. It has been shown that immune abnormalities occur in a substantial number of individuals with ASD. Identifying subgroups with immune system dysregulation and linking specific cellular immunophenotypes to different symptoms would be key to defining a group of patients with immune abnormalities as a major etiology underlying behavioral symptoms. These determinations would provide the opportunity to investigate causative treatments for a defined patient group that may specifically benefit from such an approach. This review summarizes recent insights into immune system dysfunction in individuals with ASD and discusses the potential implications for future therapies.

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

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

Xueshuantong injection (lyophilized) combined with salvianolate lyophilized injection protects against focal cerebral ischemia/reperfusion injury in rats through attenuation of oxidative stress

Salvianolate lyophilized injection (SLI) and Xueshuantong injection (lyophilized) (XST) are two herbal standardized preparations that have been widely used in China for the treatment of acute cerebral infarction. In this study, we investigated the neuroprotective effects of SLI combined with XST in a rat model of middle cerebral artery occlusion-reperfusion (MCAO/R). Wistar rats were subjected to 1.5 h of MCAO followed by reperfusion for 3 h, then were treated with SLI or XST alone, or with their combinations via tail vein injection daily for 3 d. Edaravone (EDI, 6 mg·kg^-1·d^-1) was used as a positive control drug, We showed that administration of a combination of 1X1S (XST 100 mg·kg^-1·d^-1 plus SLI 21 mg·kg^-1·d^-1) more effectively protected the ischemic brains than SLI or XST used alone. Administration of 1X1S not only significantly decreased neurological deficit scores and infarct volumes and increased regional cerebral blood flow, but also inhibited the activation of both microglia and astrocytes in the hippocampus. Furthermore, administration of 1X1S significantly decreased the levels of MDA and ROS with concomitant increases in the levels of antioxidant activity (SOD, CAT and GSH) in the brain tissues as compared with SLI and XST used alone. Moreover, administration of 1X1S remarkably upregulated the expression of Nrf-2, HO-1 and NQO-1, and downregulated the expression of Keap1 and facilitated the nuclear translocation of Nrf-2 in the brain tissues as compared with XST used alone. Our study demonstrates that a combination of 1X1S effectively protects MCAO/R injury via suppressing oxidative stress and the Nrf-2/Keap1 pathway.

Valproic acid attenuates manganese-induced reduction in expression of GLT-1 and GLAST with concomitant changes in murine dopaminergic neurotoxicity

Exposure to elevated levels of manganese (Mn) causes manganism, a neurological disorder with similar characteristics to those of Parkinson's disease (PD). Valproic acid (VPA), an antiepileptic, is known to inhibit histone deacetylases and exert neuroprotective effects in many experimental models of neurological disorders. In the present study, we investigated if VPA attenuated Mn-induced dopaminergic neurotoxicity and the possible mechanisms involved in VPA's neuroprotection, focusing on modulation of astrocytic glutamate transporters (glutamate aspartate transporter, GLAST and glutamate transporter 1, GLT-1) and histone acetylation in H4 astrocyte culture and mouse models. The results showed that VPA increased promoter activity, mRNA/protein levels of GLAST/GLT-1 and glutamate uptake, and reversed Mn-reduced GLAST/GLT-1 in in vitro astrocyte cultures. VPA also attenuated Mn-induced reduction of GLAST and GLT-1 mRNA/protein levels in midbrain and striatal regions of the mouse brain when VPA (200 mg/kg, i.p., daily, 21 d) was administered 30 min prior to Mn exposure (30 mg/kg, intranasal instillation, daily, 21 d). Importantly, VPA attenuated Mn-induced dopaminergic neuronal damage by reversing Mn-induced decrease of tyrosine hydroxylase (TH) mRNA/protein levels in the nigrostriatal regions. VPA also reversed Mn-induced reduction of histone acetylation in astrocytes as well as mouse brain tissue. Taken together, VPA exerts attenuation against Mn-induced decrease of astrocytic glutamate transporters parallel with reversing Mn-induced dopaminergic neurotoxicity and Mn-reduced histone acetylation. Our findings suggest that VPA could serve as a potential neuroprotectant against Mn neurotoxicity as well as other neurodegenerative diseases associated with excitotoxicity and impaired astrocytic glutamate transporters.

Anti-inflammatory Effects of Valproic Acid in a Rat Model of Renal Ischemia/Reperfusion Injury: Alteration in Cytokine Profile

Valporic acid (VPA) has been implicated to have anti-inflammatory and anti-oxidant activities in several ischemic/reperfusion (I/R) injury models. This study intended to evaluate whether VPA could affect the inflammatory/anti-inflammatory cytokines balance and severity of renal I/R injury in rat. I/R injury was induced in two groups of animals, vehicle normal saline and VPA-treated (IP injection, 150 mg/kg) rats, by 45 min occlusion of both left and right renal arteries followed by 3, 24 and 120 h reperfusion in separate groups. After each time point, kidneys and blood samples were collected for cytokine genes (TNF-α, IL-1β, IL-10 and TGF-β) expression analysis and histological examinations in the kidney tissues. Serum creatinine levels were measured for evaluation of renal function. We observed significantly downregulated mRNA expressions for IL-1β and TNF-α in blood and tissue samples 24 and 120 h post I/R injury in VPA-treated animals compared to control groups (P < 0.0001). On the other hand, mRNA expression levels for IL-10 and TGF-β were significantly increased in the blood samples from VPA-treated animals at two time points after I/R injury (P < 0.0001) and at 120 h in tissue samples (P < 0.001). Histopathology analysis showed downgraded ischemic changes in VPA group compared to sham control. Also, decreased serum creatinine levels were observed in VPA-treated animals particularly 120 h post I/R injury (P < 0.0001) that was correlated with less pathological changes in this group. Our results indicate that VPA can attenuate pro-inflammatory responses and augment the anti-inflammatory condition in favor of faster renal recovery from ischemic changes and improved renal function after renal I/R injury.

Valproic acid prevents glucocorticoid‑induced osteonecrosis of the femoral head of rats

Glucocorticoids (GCs) are the most common cause of atraumatic osteonecrosis of the femoral head (ONFH) because their effect compromises the osteogenic capability of bone marrow-derived mesenchymal stem cells (BMSCs). Valproic acid (VPA) is a widely used anti-epileptic and anticonvulsant drug. Previous studies have reported that VPA promotes osteogenic differentiation of MSCs in vitro and osteogenesis in vivo as a histone deacetylase (HDAC) inhibitor. The purpose of the present study was to investigate the efficacy of VPA as a precautionary treatment of ONFH after GC treatment in rats. In vitro, the effect of VPA, dexamethasone or a combination treatment of the two on the proliferation and osteogenic differentiation of human BMSCs was assessed using a Cell Counting Kit-8 and apoptosis assays, and by measuring the expression of proteins associated with osteogenesis. In vivo, a GC-induced ONFH model was established in rats and VPA was added during GC treatment to investigate the preventive effect of VPA against ONFH. Rat BMSCs were also extracted to investigate the osteogenic capacity. The results of micro-computed tomography scanning, angiography of the femoral head and histological and immunohistochemical analyses indicated that 11 of 15 rats induced with methylprednisolone (MP) presented with ONFH, while only 2 of 15 rats treated with a combination of MP and VPA developed ONFH. VPA produced beneficial effects on subchondral bone trabeculae in the femoral head with significant preservation of bone volume and blood supply, as well as improved osteogenic capability of BMSCs compared with those in rats treated with GC alone. In conclusion, VPA attenuated the inhibitory effect of GC on BMSC proliferation and osteogenesis by inhibiting apoptosis and elevating the expression of proteins associated with osteogenesis, which may contribute to the prevention of GC-induced ONFH in rats.

Mito-Tempo prevents nicotine-induced exacerbation of ischemic brain damage

Nicotine may contribute to the pathogenesis of cerebrovascular disease via the generation of reactive oxygen species (ROS). Overproduction of ROS leads to brain damage by intensifying postischemic inflammation. Our goal was to determine the effect of Mito-Tempo, a mitochondria-targeted antioxidant, on ischemic brain damage and postischemic inflammation during chronic exposure to nicotine. Male Sprague-Dawley rats were divided into four groups: control, nicotine, Mito-Tempo-treated control, and Mito-Tempo-treated nicotine. Nicotine (2 mg·kg^-1·day^-1) was administered via an osmotic minipump for 4 wk. Mito-Tempo (0.7 mg·kg^-1·day^-1 ip) was given for 7 days before cerebral ischemia. Transient focal cerebral ischemia was induced by occlusion of the middle cerebral artery for 2 h. Brain damage and inflammation were evaluated after 24 h of reperfusion by measuring infarct volume, expression of adhesion molecules, activity of matrix metalloproteinase, brain edema, microglial activation, and neutrophil infiltration. Nicotine exacerbated infarct volume and worsened neurological deficits. Nicotine did not alter baseline ICAM-1 expression, matrix metallopeptidase-2 activity, microglia activation, or neutrophil infiltration but increased these parameters after cerebral ischemia. Mito-Tempo did not have an effect in control rats but prevented the chronic nicotine-induced augmentation of ischemic brain damage and postischemic inflammation. We suggest that nicotine increases brain damage following cerebral ischemia via an increase in mitochondrial oxidative stress, which, in turn, contributes to postischemic inflammation. NEW & NOTEWORTHY Our findings have important implications for the understanding of mechanisms contributing to increased susceptibility of the brain to damage in smokers and users of nicotine-containing tobacco products.

Potential application of the oxidative nucleic acid damage biomarkers in detection of diseases

Reactive oxygen species (ROS) are generated after exposure to harmful environmental factors and during normal cellular metabolic processes. The balance of the generating and scavenging of ROS plays a significant role in living cells. The accumulation of ROS will lead to oxidative damage to biomolecules including nucleic acid. Although many types of oxidative nucleic acid damage products have been identified, 8-oxo-7,8-dihydro-2’-deoxyguanosine (8-oxodG) and 8-oxo-7,8-dihydroguanosine (8-oxoG) has been commonly chosen as the biomarkers of oxidative damage to DNA and RNA, respectively. It has been demonstrated that oxidative damage to nucleic acid is an initiator in pathogenesis of numerous diseases. Thus, oxidative nucleic acid damage biomarkers have the potential to be utilized for detection of diseases. Herein, we reviewed the relationship of oxidative nucleic acid damage and development of various diseases including cancers (colorectal cancer, gastrointestinal cancer, breast cancer, lung cancer, epithelial ovarian carcinoma, esophageal squamous cell carcinoma), neurodegenerative disorders and chronic diseases (diabetes and its complications, cardiovascular diseases). The potential of oxidative nucleic acid damage biomarkers for detection of diseases and drug development were described. Moreover, the approaches for detection of these biomarkers were also summarized.

Rufinamide pretreatment attenuates ischemia-reperfusion injury in the gerbil hippocampus

OBJECTIVES

Rufinamide, a voltage-gated sodium channel (VGSC) blocker, is widely used for the clinical treatment of seizures associated with Lennox-Gastaut syndrome. Previous studies have demonstrated that VGSC blockers have neuroprotective properties against ischemic damage following experimental cerebral ischemia. However, protective effects of rufinamide against cerebral ischemic insults have not been addressed. Therefore, in the present study, we firstly examined neuroprotective effects of rufinamide using a gerbil model of transient global cerebral ischemia.

METHODS

Gerbils were established by the occlusion of common carotid arteries for 5 min. The gerbils were divided into vehicle-treated sham-operated group, vehicle-treated ischemia-operated group, 50 and 100 mg/kg rufinamide-treated sham-operated groups, and 50 and 100 mg/kg rufinamide-treated ischemia-operated groups. Rufinamide was administrated intraperitoneally once daily for 3 days before ischemic surgery. To examine neuroprotective effects of rufinamide, we carried out cresyl violet staining, neuronal nuclear antigen immunohistochemistry and Fluoro-Jade B histofluorescence staining. In addition, we examined gliosis using immunohistochemistry for glial fibrillary acidic protein (a marker for astrocytes) and ionized calcium-binding adapter molecule 1 (a marker for microglia).

RESULTS

We found that pre-treatment with 100 mg/kg of rufinamide effectively protected pyramidal neurons in the hippocampal cornus ammonis 1 (CA1) area after transient global cerebral ischemia. In addition, pre-treatment with 100 mg/kg of rufinamide significantly attenuated activations of astrocytes and microglia in the ischemic CA1 area.

DISCUSSION

These findings suggest that rufinamide can display neuroprotective effect against cerebral ischemic insults and that its neuroprotective effect may involve the attenuation of ischemia-induced glial activation.

Targeting Oxidative Stress for Treatment of Glaucoma and Optic Neuritis

Glaucoma is a neurodegenerative disease of the eye and it is one of the leading causes of blindness. Glaucoma is characterized by progressive degeneration of retinal ganglion cells (RGCs) and their axons, namely, the optic nerve, usually associated with elevated intraocular pressure (IOP). Current glaucoma therapies target reduction of IOP, but since RGC death is the cause of irreversible vision loss, neuroprotection may be an effective strategy for glaucoma treatment. One of the risk factors for glaucoma is increased oxidative stress, and drugs with antioxidative properties including valproic acid and spermidine, as well as inhibition of apoptosis signal-regulating kinase 1, an enzyme that is involved in oxidative stress, have been reported to prevent glaucomatous retinal degeneration in mouse models of glaucoma. Optic neuritis is a demyelinating inflammation of the optic nerve that presents with visual impairment and it is commonly associated with multiple sclerosis, a chronic demyelinating disease of the central nervous system. Although steroids are commonly used for treatment of optic neuritis, reduction of oxidative stress by approaches such as gene therapy is effective in ameliorating optic nerve demyelination in preclinical studies. In this review, we discuss oxidative stress as a therapeutic target for glaucoma and optic neuritis.

Valproic Acid and Lithium Meditate Anti-Inflammatory Effects by Differentially Modulating Dendritic Cell Differentiation and Function

Valproic acid (VPA), with inhibition activity mainly toward histone deacetylase (HDAC) and Glycogen Synthase Kinase (GSK)-3, and lithium, with inhibition activity mainly toward GSK-3, are both prescribed in clinical as mood-stabilizers and anticonvulsants for the control of bipolar disorder. This study aims to compare the immuno-modulation activities of VPA and lithium, especially on the differentiation and functions of dendritic cells (DC). Our data show that treatment with VPA or lithium effectively alleviated the severity of collagen-induced arthritis triggered by LPS in mice. Both agents reduced the serum level of IL-6 and IL-10 after LPS challenge in mice. VPA and lithium both induce significant down-regulation of group I CD1 expression and secretion of IL-6 during differentiation of human monocyte-derived immature DC, while they differ in the induction of CD83 and CD86 expression, secretion of IL-8, IL-10, and TNF-α. Upon stimulation of immature DC with LPS, VPA, and lithium both reduced the secretion of IL-6 and TNF-α. However, only lithium significantly increased the production of IL-10, while VPA increased the production of IL-8 but substantially reduce the secretion of IL-10 and IL-23. Treatment with VPA resulted in a reduced capacity of LPS-stimulated DC to promote the differentiation of T helper 17 cells that are critical in the promotion of inflammatory responses. Taken together, our results suggest that VPA and lithium may differentially modulate inflammation through regulating the capacity of DC to mediate distinct T cell responses, and they may provide a complementary immunomodulatory effects for the treatment of inflammation-related diseases. J. Cell. Physiol. 232: 1176-1186, 2017. © 2016 Wiley Periodicals, Inc.

The effect of mood-stabilizing drugs on cytokine levels in bipolar disorder: A systematic review

OBJECTIVES

Cytokine level alterations suggest a role for the immune system in the pathophysiology of bipolar disorder (BD). Pharmacotherapy is an important confounding factor in clinical research on cytokine levels. In this systematic review we collate the evidence on blood cytokine levels in medication-free BD and the effects of single mood-stabilizing drugs on these levels.

METHODS

A systematic review was conducted according to the PRISMA statement. We searched the Pubmed and Embase databases for clinical studies reporting either on cytokine levels in medication-free BD or on the effects of single mood-stabilizing drugs on cytokine levels in BD.

RESULTS

Of the 564 articles screened, 17 were included. Fourteen articles report on medication-free patients with BD and indicate state-related cytokine alterations. Six articles discuss the effect of lithium. Whereas no data on short-term effects of lithium were found, ≥2 months lithium use in euthymic populations is associated with normal cytokine levels. Two studies report no effect of valproate and no studies were found on carbamazepine, lamotrigine or antipsychotics.

LIMITATIONS

The available studies are characterized by a broad methodological heterogeneity and limited replication between studies.

CONCLUSIONS

This systematic review suggests the presence of state-related cytokine level alterations in medication-free BD with most evidence pointing to a proinflammatory cytokine response in mania. Euthymia and long-term lithium use are associated with normal cytokine levels. To improve our understanding of the impact of mood-stabilizing drugs on cytokine levels, longitudinal studies with medication-free baseline, randomized controlled single-drug treatment protocols and close mood state monitoring are needed.

Fatty acids and their therapeutic potential in neurological disorders

There is little doubt that we are what we eat. Fatty acid supplementation and diets rich in fatty acids are being promoted as ways to a healthier brain. Short chain fatty acids are a product of intestinal microbiota metabolism of dietary fibre; and their derivatives are used as an anti-convulstant. They demonstrated therapeutic potential in neurodegenerative conditions as HDAC inhibitors; and while the mechanism is not well understood, have been shown to lower amyloid β in Alzheimer's Disease in preclinical studies. Medium chain fatty acids consumed as a mixture in dietary oils can induce ketogenesis without the need for a ketogentic diet. Hence, this has the potential to provide an alternative energy source to prevent neuronal cell death due to lack of glucose. Long chain fatty acids are commonly found in the diet as omega fatty acids. They act as an anti-oxidant protecting neuronal cell membranes from oxidative damage and as an anti-inflammatory mediator in the brain. We review which agents, from each fatty acid class, have the most therapeutic potential for neurological disorders (primarily Alzheimer's disease, Parkinson's disease, Autism Spectrum Disorder as well as possible applications to traumatic brain injury), by discussing what is known about their biological mechanisms from preclinical studies.

Hydrogen-rich water attenuates brain damage and inflammation after traumatic brain injury in rats

Inflammation and oxidative stress are the two major causes of apoptosis after traumatic brain injury (TBI). Most previous studies of the neuroprotective effects of hydrogen-rich water on TBI primarily focused on antioxidant effects. The present study investigated whether hydrogen-rich water (HRW) could attenuate brain damage and inflammation after traumatic brain injury in rats. A TBI model was induced using a controlled cortical impact injury. HRW or distilled water was injected intraperitoneally daily following surgery. We measured survival rate, brain edema, blood-brain barrier (BBB) breakdown and neurological dysfunction in all animals. Changes in inflammatory cytokines, inflammatory cells and Cho/Cr metabolites in brain tissues were also detected. Our results demonstrated that TBI-challenged rats exhibited significant brain injuries that were characterized by decreased survival rate and increased BBB permeability, brain edema, and neurological dysfunction, while HRW treatment ameliorated the consequences of TBI. HRW treatment also decreased the levels of pro-inflammatory cytokines (TNF-α, IL-1β and HMGB1), inflammatory cell number (Iba1) and inflammatory metabolites (Cho) and increased the levels of an anti-inflammatory cytokine (IL-10) in the brain tissues of TBI-challenged rats. In conclusion, HRW could exert a neuroprotective effect against TBI and attenuate inflammation, which suggests HRW as an effective therapeutic strategy for TBI patients.

Valproic Acid Pretreatment Reduces Brain Edema in a Rat Model of Surgical Brain Injury

Surgically induced brain injury (SBI) results in brain edema and neurological decline. Valproic acid (VA) has been shown to be neuroprotective in several experimental brain diseases. In this study, we investigated the pretreatment effect of VA in a rat model of SBI. A total of 57 male Sprague-Dawley rats were use in four groups: sham, SBI + vehicle, SBI + low dose (100 mg/kg) VA, and SBI + high dose (300 mg/kg) VA. SBI was induced by partially resecting right frontal lobes. Shams underwent identical surgical procedures without brain resection. VA or vehicle was administered subcutaneously 30 min prior to SBI. At 24 and 72 h post SBI, neurobehavior and brain water content were assessed as well as matrix metalloproteinases (MMPs) activities. There was significantly higher brain water content within the right frontal lobe in SBI rats than in shams. Without neurobehavioral improvements, the low-dose but not high-dose VA significantly reduced brain edema at 24 h post SBI. The protection tends to persist to 72 h post SBI. At 24 h post SBI, low-dose VA did not significantly reduce the elevated MMP-9 activity associated with SBI. In conclusion, VA pretreatment attenuated brain edema at 24 h after SBI but lacked MMP inhibition. The single dose VA was not associated with neurobehavioral benefits.

High-fat diet-induced obesity exacerbates kainic acid-induced hippocampal cell death

BACKGROUND

Obesity has deleterious effects on the brain, and metabolic dysfunction may exacerbate the outcomes of seizures and brain injuries. However, it is unclear whether obesity affects excitotoxicity-induced neuronal cell death. The purpose of this study was to investigate the effects of a high-fat diet (HFD) on neuroinflammation and oxidative stress in the hippocampus of kainic acid (KA)-treated mice.

RESULTS

Mice were fed with a HFD or normal diet for 8 weeks and then received a systemic injection of KA. HFD-fed mice showed hypercholesterolemia, insulin resistance, and hepatic steatosis. HFD-fed mice showed greater susceptibility to KA-induced seizures, an increased number of terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL)-positive cells, neuroinflammation, and oxidative stress. Furthermore, we found that KA treatment increased HFD-induced calpain1, nuclear factor E2-related factor 2, and heme oxygenase-1 expression in the hippocampus.

CONCLUSIONS

These findings imply that complex mechanisms affected by obesity-induced systemic inflammation, neuroinflammation, ER stress, calcium overload, and oxidative stress may contribute to neuronal death after brain injury.

Innate and adaptive immune response in stroke: Focus on epigenetic regulation

Inflammation and immune response play a pivotal role in the pathophysiology of ischemic stroke giving their contribution to tissue damage and repair. Emerging evidence supports the involvement of epigenetic mechanisms such as methylation, histone modification and miRNAs in the pathogenesis of stroke. Interestingly, epigenetics can influence the molecular events involved in ischemic injury by controlling the switch from pro- to anti-inflammatory response, however, this is still a field to be fully explored. The knowledge of epigenetic processes could to allow for the discovery of more sensitive and specific biomarkers for risk, onset, and progression of disease as well as further novel tools to be used in both primary prevention and therapy of stroke. Indeed, studies performed in vitro and in small animal models seem to suggest a neuroprotective role of HDAC inhibitors (e.g. valproic acid) and antagomir (e.g. anti-miR-181a) in ischemic condition by modulation of both immune and inflammatory pathways. Thus, the clinical implications of altered epigenetic mechanisms for the prevention of stroke are very promising but clinical prospective studies and translational approaches are still warranted.

Effect of valproic acid combined with therapeutic hypothermia on neurologic outcome in asphyxial cardiac arrest model of rats

BACKGROUNDS

Valproic acid (VPA) has been reported to have survival and neuroprotective effects in a cardiac arrest rat model. This study was designed to investigate the effect of VPA combined with therapeutic hypothermia (HT) in an asphyxial cardiac arrest rat model.

METHODS

Rats were subjected to 6 minutes of asphyxial cardiac arrest. Cardiopulmonary resuscitation was performed and then the randomly allocated to 1 of 4 groups (normal saline [NS]/normothermia [NT], VPA/NT, NS/HT, and VPA/HT). Hypothermia (32.5°C ± 0.5°C, 4 hours of HT and 2 hours of rewarming) or NT (37°C ± 0.5°C for 6 hours) was applied, and VPA (300 mg/kg) or NS was administered immediately after the return of spontaneous circulation. Neurologic deficit score was measured, and a tape removal test was performed for 3 days. Histologic injury of hippocampus was evaluated.

RESULTS

Valproic acid significantly improved neurologic deficit score at 48 and 72 hours in the NT-treated rats and at 72 hours in the HT-treated rats (all P < .05). Although the latency and success rate were not significantly different between the VPA/NT and NS/NT groups, the VPA/HT group showed significantly lower latency and higher success rates compared to the NS/HT group (P < .05). The histologic injury score in the hippocampal CA1 sector was significantly lower in the VPA/NT group than the NS/NT group (P < .05) and showed a tendency to be decreased in the VPA/HT group compared with the NS/HT group (P = .06).

CONCLUSION

In an asphyxial cardiac arrest rat model, administration of VPA improved neurologic outcomes and added a neuroprotective effect to HT.

Small bioactive molecules as dual functional co-dopants for conducting polymers

Scanning electron microscope image of surface morphology of conducting polymer PEDOT doped with bioactive molecules.

Valproic acid prevents NMDA-induced retinal ganglion cell death via stimulation of neuronal TrkB receptor signaling

Valproic acid (VPA) is widely prescribed for treatment of epilepsy, mood disorders, migraines, and neuropathic pain. It exerts its therapeutic benefits through multiple mechanisms, including enhancement of GABAergic activity, activation of prosurvival protein kinases, and inhibition of histone deacetylase. Increasing evidence suggests that VPA possesses neuroprotective properties. We examined neuroprotective effects of VPA in an N-methyl-d-aspartate (NMDA) excitotoxicity model, which mimics some of the pathological features of glaucoma. In vivo retinal imaging using optical coherence tomography revealed that NMDA-induced retinal degeneration was suppressed in the VPA-treated retina, and histological analyses confirmed that VPA reduced retinal ganglion cell death. In vivo electrophysiological analyses demonstrated that visual impairment was prevented in the VPA-treated retina, clearly establishing both histological and functional effects of VPA. Brain-derived neurotrophic factor (BDNF) expression was up-regulated in Müller glial cells, and neuroprotective effects of VPA on retinal ganglion cells were significantly reduced in a conditional knockout mouse strain with deletion of tropomyosin receptor kinase B (TrkB), a receptor for BDNF from retinal ganglion cells. The results show that VPA stimulates BDNF up-regulation in Müller glial cells and provides direct evidence that neuronal TrkB is important in VPA-mediated neuroprotection. Also, VPA suppresses oxidative stress induced by NMDA in the retina. Our findings raise intriguing possibilities that the widely prescribed drug VPA may be useful for treatment of glaucoma.

Decreased GFAP expression and improved functional recovery in contused spinal cord of rats following valproic acid therapy

Many studies have illustrated that much of the post-traumatic degeneration of the spinal cord cells is caused by the secondary mechanism. The aim of this study is to evaluate the effect of the anti-inflammatory property of valproic acid (VPA) on injured spinal cords (SC). The rats with the contused SC received intraperitoneal single injection of VPA (150, 200, 300, 400 or 500 mg/kg) at 2, 6, 12 and 24 h post-injury. Basso-Beattie-Bresnahan (BBB) test and H-reflex evaluated the functional outcome for 12 weeks. The SC were investigated 3 months post-injury using morphometry and glial fibrillary acid protein (GFAP) expression. Reduction in cavitation, H/M ratio, BBB scores and GFAP expression in the treatment groups were significantly more than that of the untreated one (P < 0.05). The optimal improvement in the condition of the contused rats was in the ones treated at the acute phase of injury with 300 mg/kg of VPA at 12 h post-injury, they had the highest increase in BBB score and decrease in astrogliosis and axonal loss. We conclude that treating the contused rats with 300 mg/kg of VPA at 12 h post-injury improves the functional outcome and reduces the traumatized SC gliosis.