Neuroprotective and neurotrophic curcuminoids to treat stroke: a translational perspective

Neuroprotective, Anti-inflammatory Effect of Furanochrome, Visnagin Against Middle Cerebral Ischemia-Induced Rat Model

In recent years, the medical field had significantly progressed to a greater extent which was evidenced with increased life expectancy and decreased mortality rate. Due to the growth of medical field, numerous communicable diseases are prevented and eradicated, whereas the non-communicable disease incidence has been increased globally. One such non-communicable disease which threatens the global population is stroke. Stroke tends to be the second leading cause of death and disability in older population. In lower- and middle-income countries, increased incidence rate of stroke was also evidenced in younger population which is alarming. Lifestyle changes, poor physical activity, stress, consumption of alcohol, oral contraception, and smoking tend to be the causative agents of stroke. Since thrombus formation is the major pathology of stroke, drugs were targeted to thrombolysis. Currently thrombolytic, antiplatelet, and anticoagulant therapies were given for the stroke patients. But the recovery rate of stroke patients with available drugs is very slow. Hence, it is a need of today to discover a drug with increased recovery rate and decreased or nil side effects. Phytochemicals are the best options to treat such non-communicable chronic diseases. Visnagin is one such compound which is used to regulate blood pressure, treat kidney stones, tumors of bile duct, renal colic, and whooping cough. It possesses anti-inflammatory, neuroprotective, and cardioprotective properties; it was also proven to treat epileptic seizures. In this study, the anti-ischemic effect of a furanochrome visnagin was assessed in in vivo rat model. Middle cerebral ischemic/reperfusion was induced in healthy male Sprague Dawley rats and treated with different concentrations of visnagin. The neuroprotective effect of visnagin against cerebral ischemia-induced rats was assessed by analyzing the neurological score, brain edema, infract volume, and Evans blue leakage. The anti-inflammatory property of visnagin was assessed by quantifying proinflammatory cytokines in serum and brain tissues of cerebral ischemia-induced rats. Prostaglandin E-2, COX-2, and NFκ-β were estimated to assess the anti-ischemic effect of visnagin. Histopathological analysis with H&E staining was performed to confirm the neuroprotective effect of visnagin against cerebral ischemia. Our results authentically confirm that visnagin has prevented the inflammation in brain region of cerebral ischemia-induced rats. The neurological scoring and the quantification of PGE-2, COX-2, and NFκ-β prove the anti-ischemic effect of visnagin. Furthermore, the histopathological analysis of hippocampal region provides evidence to the neuroprotective effect of visnagin against cerebral ischemia. Overall, our study confirms visnagin as a potent alternative drug to treat stroke.

Bioactive Compounds from the Zingiberaceae Family with Known Antioxidant Activities for Possible Therapeutic Uses

The Zingiberaceae family is a rich source of diverse bioactive phytochemicals. It comprises about 52 genera and 1300 species of aromatic flowering perennial herbs with characteristic creeping horizontal or tuberous rhizomes. Notable members of this family include ginger (Zingiber officinale Roscoe), turmeric (Curcuma longa L.), Javanese ginger (Curcuma zanthorrhiza Roxb.), and Thai ginger (Alpinia galanga L.). This review focuses on two main classes of bioactive compounds: the gingerols (and their derivatives) and the curcuminoids. These compounds are known for their antioxidant activity against several maladies. We highlight the centrality of their antioxidant activities with notable biological activities, including anti-inflammatory, antidiabetic, hepatoprotective, neuroprotective, antimicrobial, and anticancer effects. We also outline various strategies that have been applied to enhance these activities and make suggestions for research areas that require attention.

Herbal drugs and natural bioactive products as potential therapeutics: A review on pro-cognitives and brain boosters perspectives

Memory, one of the most vital aspects of the human brain, is necessary for the effective survival of an individual. 'Memory' can be defined in various ways but in an overall view, memory is the retention of the information that the brain grasps. Different factors are responsible for the disbalance in the brain's hippocampus region and the acetylcholine level, which masters the memory and cognitive functions. Plants are a source of pharmacologically potent drug molecules of high efficacy. Recently herbal medicine has evolved rapidly, gaining great acceptance worldwide due to their natural origin and fewer side effects. In this review, the authors have discussed the mechanisms and pharmacological action of herbal bioactive compounds to boost memory. Moreover, this review presents an update of different herbs and natural products that could act as memory enhancers and how they can be potentially utilized in the near future for the treatment of severe brain disorders. In addition, the authors also discuss the differences in biological activity of the same herb and emphasize the requirement for a higher standardization in cultivation methods and plant processing. The demand for further studies evaluating the interactions of herbal drugs is mentioned.

Systematic Study of Crucial Transcription Factors of Coptidis rhizoma Alkaloids against Cerebral Ischemia-Reperfusion Injury

Coptidis rhizoma alkaloids (CRAs), extracted from Coptidis rhizoma, have been indicated to play important neuroprotective roles, but the mechanism underlying has not been determined, especially from the perspective of transcription factors (TFs). In this study, crucial TFs involved in the protective activity of CRA were revealed based on RNA-Seq technology, proteomics, and network pharmacological analysis of the effects of CRA on middle cerebral artery occlusion-mediated cerebral ischemia-reperfusion (I/R) injury. Importantly, CRA significantly reduced the infarction rate and neurological deficiency score. Moreover, CRA significantly decreased the levels of TNF-α, MCP-1, and IL-1β. In addition, seven TFs, including Ncor1, Smad1, Bhlhe41, Stat3, Sp100, Satb2, and Lrpprc, were found to be crucial TFs, and five of these TFs were associated with inflammation. Furthermore, eight compounds in CRA were associated with the identified TFs through network pharmacological analysis. The alteration of Lrpprc and Sabt2 was further confirmed by measuring their downstream genes, including Pigg, Hhatl, Wdr77, Mpped1, Arpp21, Ppfia3, Rims1, and Cacna2d1 by reverse transcriptase polymerase chain reaction. Thus, these seven TFs may be important targets in CRA-mediated protection against I/R injury. This research provides a new view of the protective effect of CRA against cerebral I/R injury and reveals new therapeutic targets for treating cerebral ischemia.

Ameliorative Role of Nutraceuticals on Neurodegenerative Diseases Using the Drosophila melanogaster as a Discovery Model to Define Bioefficacy

Neurodegeneration is the destruction of neurons, and once the neurons degenerate they can't revive. This is one of the most concerned health conditions among aged population, more than ∼70% of the elderly people are suffering from neurodegeneration. Among all of the neurodegenerative diseases, Alzheimer's disease (AD), Parkinson's disease (PD) and Poly-glutamine disease (Poly-Q) are the major one and affecting most of the people around the world and posing excessive burden on the society. In order to understand this disease in non-human animal models it is pertinent to examine in model organism and various animal model are being used for such diseases like rat, mice and non-vertebrate model like Drosophila. Drosophila melanogaster is one of the best animal proven by several eminent scientist and had received several Nobel prizes for uncovering mechanism of human related genes and highly efficient model for studying neurodegenerative diseases due to its great affinity with human disease-related genes. Another factor is also employed to act as therapeutic or preventive method that is nutraceuticals. Nutraceuticals are functional natural compounds with antioxidant properties and had extensively showed the neuroprotective effect in different organisms. These nutraceuticals having antioxidant properties act through scavenging free radicals or by increasing endogenous cellular antioxidant defense molecules. For the best benefit, we are trying to utilize these nutraceuticals, which will have no or negligible side effects. In this review, we are dealing with various types of such nutraceuticals which have potent value in the prevention and curing of the diseases related to neurodegeneration.HighlightsNeurodegeneration is the silently progressing disease which shows its symptoms when it is well rooted.Many chemical drugs (almost all) have only symptomatic relief with side effects.Potent mechanism of neurodegeneration and improvement effect by nutraceuticals is proposed.Based on the Indian Cuisine scientists are trying to find the medicine from the food or food components having antioxidant properties.The best model to study the neurodegenerative diseases is Drosophila melanogaster.Many nutraceuticals having antioxidant properties have been studied and attenuated various diseases are discussed.

Neuroprotection by cattle encephalon glycoside and ignotin beyond the time window of thrombolysis in ischemic stroke

Cattle encephalon glycoside and ignotin (CEGI) injection is known as a multi-target neuroprotective drug that contains numerous liposoluble molecules, such as polypeptides, monosialotetrahexosyl ganglioside (GM-1), free amino acids, hypoxanthine and carnosine. CEGI has been approved by the Chinese State Food and Drug Administration and widely used in the treatments of various diseases, such as stroke and Alzheimer’s disease. However, the neuroprotective effects of CEGI beyond the time window of thrombolysis (within 4.5 hours) on acute ischemic stroke remain unclear. This study constructed a rat middle cerebral artery occlusion model by suture-occluded method to simulate ischemic stroke. The first daily dose was intraperitoneally injected at 8 hours post-surgery and the CEGI treatments continued for 14 days. Results of the modified five-point Bederson scale, beam balance test and rotameric test showed the neurological function of ischemic stroke rats treated with 4 mL/kg/d CEGI improved significantly, but the mortality within 14 days did not change significantly. Brain MRI and 2,3,5-triphenyltetrazolium chloride staining confirmed that the infarct size in the 4 mL/kg/d CEGI-treated rats was significantly reduced compared with ischemic insult only. The results of transmission electron microscopy and double immunofluorescence staining showed that the hippocampal neuronal necrosis in the ischemic penumbra decreased whereas the immunopositivity of new neuronal-specific protein doublecortin and the percentage of Ki67/doublecortin positive cells increased in CEGI-treated rats compared with untreated rats. Our results suggest that CEGI has an effective neuroprotective effect on ischemic stroke when administered after the time window of thrombolysis. The study was approved by the Animal Ethics Committee of The Third Military Medical University, China.

Celastrol Dilates and Counteracts Ethanol-Induced Constriction of Cerebral Arteries

The increasing recognition of the role played by cerebral artery dysfunction in brain disorders has fueled the search for new cerebrovascular dilators. Celastrol, a natural triterpene undergoing clinical trials for treating obesity, exerts neuroprotection, which was linked to its antioxidant/anti-inflammatory activities. We previously showed that celastrol fit pharmacophore criteria for activating calcium- and voltage-gated potassium channels of large conductance (BK channels) made of subunits cloned from cerebrovascular smooth muscle (SM). These recombinant BK channels expressed in a heterologous system were activated by celastrol. Activation of native SM BK channels is well known to evoke cerebral artery dilation. Current data demonstrate that celastrol (1-100 µM) dilates de-endothelialized, ex vivo pressurized middle cerebral arteries (MCAs) from rats, with EC₅₀ = 45 µM and maximal effective concentration (E_max)= 100 µM and with MCA diameter reaching a 10% increase over vehicle-containing, time-matched values (P < 0.05). A similar vasodilatory efficacy is achieved when celastrol is probed on MCA segments with intact endothelium. Selective BK blocking with 1 μM paxilline blunts celastrol vasodilation. Similar blunting is achieved with 0.8 mM 4-aminopirydine, which blocks voltage-gated K⁺ channels other than BK. Using an in vivo rat cranial window, we further demonstrate that intracarotid injections of 45 μM celastrol into pial arteries branching from MCA mimics celastrol ex vivo action. MCA constriction by ethanol concentrations reached in blood during moderate-heavy alcohol drinking (50 mM), which involves SM BK inhibition, is both prevented and reverted by celastrol. We conclude that celastrol could be an effective cerebrovascular dilator and antagonist of alcohol-induced cerebrovascular constriction, with its efficacy being uncompromised by conditions that disrupt endothelial and/or BK function. SIGNIFICANCE STATEMENT: Our study demonstrates for the first time that celastrol significantly dilates rat cerebral arteries both ex vivo and in vivo and both prevents and reverses ethanol-induced cerebral artery constriction. Celastrol actions are endothelium-independent but mediated through voltage-gated (K_V) and calcium- and voltage-gated potassium channel of large conductance (BK) K⁺ channels. This makes celastrol an appealing new agent to evoke cerebrovascular dilation under conditions in which endothelial and/or BK channel function are impaired.

The efficacy and safety of salvianolic acids on acute cerebral infarction treatment: A protocol for systematic review and meta analysis

BACKGROUND

Salvianolic acids (SA) has been widely used for the treatment of acute cerebral infarction (ACI) combined with basic western medicine therapy in China. This study was aimed to evaluate the efficacy and safety of SA on ACI treatment and its influence on neurological functions, activity of daily living, and cognitive functions.

METHODS

We retrieved related articles from PubMed, the Cochrane Center Controlled Trials Register, EMBASE, Medline, Ovid, Chinese National Knowledge Infrastructure, Chinese Biomedical Literature Database, and Wanfang Database without date and language restrictions. Finally, 58 randomized controlled trials were included from 239 retrieved records. Two researchers extracted the basic information and data from included articles and assessed the quality and analysis of data by using Review Manager 5.3.

RESULTS

The administration of SA significantly increased the total clinical effective rate of ACI treatment (P < .001) and improved the National Institute of Health Stroke Scale scores, modified Rankin Scale scores, and Barthel Index scores after treatment and 3 months after ACI (P < .05). The activities of daily living scores in the SA group were significantly increased after treatment (P < .001), whereas they were remarkably decreased 3 months after ACI (P < .001) compared with that in the control group. Besides, SA profoundly promoted the recovery of Montreal Cognitive Assessment scores (P < .001). However, the use of SA increased the risk of adverse events occurrence (P = .007).

CONCLUSION

SA combined with basic western medicine treatment could promote neurological functions, daily living activities, and cognitive functions recovery of ACI patients. Although SA increased the risk of adverse events occurrence, these adverse events were easily controlled or disappeared spontaneously.

Enhanced thioredoxin, glutathione and Nrf2 antioxidant systems by safflower extract and aceglutamide attenuate cerebral ischaemia/reperfusion injury

A large number of reactive oxygen species (ROS) aggravate cerebral damage after ischaemia/reperfusion (I/R). Glutathione (GSH), thioredoxin (Trx) and nuclear factor (erythroid-derived 2)-like 2 (Nrf2) represent three major antioxidant systems and play vital roles in affecting each other in eliminating ROS. Identification of drugs targeting triple antioxidant systems simultaneously is vital for inhibiting oxidative damage after cerebral I/R. This study investigated the protective effect of safflower extract and aceglutamide (SAAG) against cerebral I/R injury through modulating multiple antioxidant systems of GSH, Trx and Nrf2 and identified each role of its component acegluatminde (AG) and safflower extract (SA) on these systems. Safflower extract and aceglutamide and its two components decreased neurological deficit scores, infarction rate, apoptosis and oxidative damage after cerebral I/R while enhanced cell viability, decreased reactive oxygen species and nitric oxide level in H₂ O₂ -induced PC12 cell model. Importantly, compared to its two components, SAAG demonstrated more effective enhancement of GSH, Nrf2 and Trx systems and a better protection against cerebral I/R injury. The enhanced antioxidant systems prevented ASK1 activation and suppressed subsequent p38 and JNK cascade-mediated apoptosis. Moreover, inhibition of Trx and Nrf2 systems by auranofin and ML385 abolished SAAG-mediated protection, respectively. Thus, enhanced triple systems by SAAG played a better protective role than those by SA or AG via inhibition of ASK1 cascades. This research provided evidence for the necessity of combination drugs from the perspective of multiple antioxidant systems. Furthermore, it also offers references for the study of combination drugs and inspires novel treatments for ischaemic stroke.

A11, a novel diaryl acylhydrazone derivative, exerts neuroprotection against ischemic injury in vitro and in vivo

There is an urgent need to develop effective therapies for ischemic stroke, but the complicated pathological processes after ischemia make doing so difficult. In the current study, we identified a novel diaryl acylhydrazone derivative, A11, which has multiple neuroprotective properties in ischemic stroke models. First, A11 was demonstrated to induce neuroprotection against ischemic injury in a dose-dependent manner (from 0.3 to 3 μM) in three in vitro experimental ischemic stroke models: oxygen glucose deprivation (OGD), hydrogen peroxide, and glutamate-stimulated neuronal cell injury models. Moreover, A11 was able to potently alleviate three critical pathological changes, apoptosis, oxidative stress, and mitochondrial dysfunction, following ischemic insult in neuronal cells. Further analysis revealed that A11 upregulated the phosphorylation levels of protein kinase B (AKT) and extracellular signal-regulated kinase (ERK) in OGD-exposed neuronal cells, suggesting joint activation of the phosphoinositide 3-kinase (PI3K)/AKT and mitogen-activated protein kinase (MEK)/ERK pathways. In rats with middle cerebral artery occlusion, single-dose administration of A11 (3 mg/kg per day, i.v.) at the onset of reperfusion significantly reduced the infarct volumes and ameliorated neurological deficits. Our study, for the first time, reports the anti-ischemic effect of diaryl acylhydrazone chemical entities, especially A11, which acts on multiple ischemia-associated pathological processes. Our results may provide new clues for the development of an effective therapeutic agent for ischemic stroke.

Curcumin Protects against Ischemic Stroke by Titrating Microglia/Macrophage Polarization

Stroke is the most common type of cerebrovascular disease and is a leading cause of disability and death. Ischemic stroke accounts for approximately 80% of all strokes. The remaining 20% of strokes are hemorrhagic in nature. To date, therapeutic options for acute ischemic stroke are very limited. Recent research suggests that shifting microglial phenotype from the pro-inflammatory M1 state toward the anti-inflammatory and tissue-reparative M2 phenotype may be an effective therapeutic strategy for ischemic stroke. The dietary phytochemical curcumin has shown promise in experimental stroke models, but its effects on microglial polarization and long-term recovery after stroke are unknown. Here we address these gaps by subjecting mice to distal middle cerebral artery occlusion (dMCAO) and administering curcumin intraperitoneally (150 mg/kg) immediately after ischemia and 24 h later. Histological studies revealed that curcumin post-treatment significantly reduced cerebral ischemic damage 3 days after dMCAO. Sensorimotor functions—as measured by the adhesive removal test and modified Garcia scores—were superior in curcumin-treated mice at 3, 5, 7 and 10 days after stroke. RT-PCR measurements revealed an elevation of M2 microglia/macrophage phenotypic markers and a reduction in M1 markers in curcumin-treated brains 3 days after dMCAO. Immunofluorescent staining further showed that curcumin treatment significantly increased the number of CD206⁺Iba1⁺ M2 microglia/macrophages and reduced the number of CD16⁺Iba1⁺ M1 cells 10 days after stroke. In vitro studies using the BV2 microglial cell line confirmed that curcumin inhibited lipopolysaccharide (LPS) and interferon-γ (IFN-γ)-induced M1 polarization. Curcumin treatment concentration-dependently reduced the expression of pro-inflammatory cytokines, including TNF-α, IL-6 and IL-12p70, in the absence of any toxic effect on microglial cell survival. In conclusion, we demonstrate that curcumin has a profound regulatory effect on microglial responses, promoting M2 microglial polarization and inhibiting microglia-mediated pro-inflammatory responses. Curcumin post-treatment reduces ischemic stroke-induced brain damage and improves functional outcomes, providing new evidence that curcumin might be a promising therapeutic strategy for stroke.

BDNF/PI3K/Akt and Nogo-A/RhoA/ROCK signaling pathways contribute to neurorestorative effect of Houshiheisan against cerebral ischemia injury in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Houshiheisan (HSHS), a classic traditional medicine prescription, has notable effects on patients with stroke AIM OF THE STUDY: To investigate the neurorestorative effects of HSHS on ischemic stroke and explore its mode of action.

MATERIALS AND METHODS

Focal cerebral ischemia models were induced by permanent middle cerebral artery occlusion (pMCAO). Male Sprague-Dawley (SD) rats were randomly divided into 5 experimental groups: sham vehicle, ischemia vehicle, pMCAO+HSHS at 5.1, 10.2g/kg, and pMCAO+Ginaton 0.028g/kg. HSHS or Ginaton was administrated 6h after pMCAO onset. Neurological function was assessed and then rats were sacrificed 7 days after MCAO. Cerebral ischemic injury was evaluated by hematoxylin and eosin (HE) staining and Neuronal nuclear antigen (NeuN) immunofluorescence analysis. The levels of BDNF were detected by enzyme linked immunosorbent assay (ELISA), and the expression levels of PI3K/Akt and Nogo-A/RhoA/ROCK2 signaling pathway were detected by western blot and quantitative real-time PCR (qRT-PCR).

RESULTS

Compared with those results of pMCAO group, HSHS 5.1 and HSHS 10.2 groups markedly improved neurological function, alleviated pathological damage, promoted the neuronal survival, increased the expression of BDNF, PI3K, Akt, in protein and mRNA, decreased the expression of Nogo-A, NgR, RhoA and ROCK2 in protein and mRNA 7 days after pMCAO.

CONCLUSIONS

The findings demonstrate that HSHS had significant therapeutic effects on ischemic stroke and it perhaps worked through the activation of BDNF/PI3K/Akt and down-regulation of Nogo-A/RhoA/ROCK signaling pathways.

Salvianolic acid A alleviates ischemic brain injury through the inhibition of inflammation and apoptosis and the promotion of neurogenesis in mice

Salvianolic acid A (SalA), a chemical type of caffeic acid trimer, has drawn great attention for its potent bioactivities against ischemia-induced injury both in vitro and in vivo. In this study, we evaluated SalA's protective effects against acute ischemic stroke by inducing middle cerebral artery occlusion/reperfusion (MCAO) injuries in mice. Treatment of the mice with SalA (50 and 100μg/kg, i.v.) at 2h after MCAO enhanced their survival rate, improved their moving activity, and ameliorated the severity of brain infarction and apoptosis seen in the mice by diminishing pathological changes such as the extensive breakdown of the blood-brain barrier (BBB), nitrosative stress, and the activation of an inflammatory transcriptional factor p65 nuclear factor-kappa B (NF-κB) and a pro-apoptotic kinase p25/Cdk5. SalA also intensively limited cortical infarction and promoted the expression of neurogenesis protein near the peri-infarct cortex and subgranular zone of the hippocampal dentate gyrus by compromising the activation of GSK3β and p25/Cdk5, which in turn upregulated β-catenin, doublecortin (DCX), and Bcl-2, most possibly through the activation of PI3K/Akt signaling via the upregulation of brain-derived neurotrophic factor. We conclude that SalA blocks inflammatory responses by impairing NF-κB signaling, thereby limiting inflammation/nitrosative stress and preserving the integrity of the BBB; SalA also concomitantly promotes neurogenesis-related protein expression by compromising GSK3β/Cdk5 activity to enhance the expression levels of β-catenin/DCX and Bcl-2 for neuroprotection.

Isoquercetin Ameliorates Cerebral Impairment in Focal Ischemia Through Anti-Oxidative, Anti-Inflammatory, and Anti-Apoptotic Effects in Primary Culture of Rat Hippocampal Neurons and Hippocampal CA1 Region of Rats

Ischemic stroke is a major disability and cause of death worldwide due to its narrow therapeutic time window. Neuroprotective agent is a promising strategy to salvage acutely ischemic brain tissue and extend the therapeutic time window for stroke treatment. In this study, we aimed to evaluate the neuroprotective effects of isoquercetin in (1) primary culture of rat hippocampal neurons exposure on oxygen and glucose deprivation and reperfusion (OGD/R) injury and (2) rats subjected to transient middle cerebral artery occlusion and reperfusion (MCAO/R) injury. The results showed that isoquercetin post-treatment reduced the infarct size, number of apoptotic cells, oxidative stress, and inflammatory response after ischemia and reperfusion injury. The underlying mechanism study indicated that the neuroprotective effects of isoquercetin were elicited via suppressing the activation of toll-like receptor 4 (TLR4), nuclear factor-kappa B (NF-κB) and caspase-1; the phosphorylation of ERK1/2, JNK1/2, and p38 mitogen-activated protein kinase (MAPK); and the secretion of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and IL-6. In addition, isoquercetin also effectively alleviated hippocampus neuron apoptosis by regulation of cyclic AMP responsive element-binding protein (CREB), Bax, Bcl-2, and caspase-3. Our report provided new considerations into the therapeutic action and the underlying mechanisms of isoquercetin to improve brain injury in individuals who have suffered from ischemic stroke. As a potent anti-inflammatory and anti-oxidative compound with neuroprotective capacities, the beneficial effects of isoquercetin when used to treat ischemic stroke and related diseases in humans warrant further studies.

Curcumin by down-regulating NF-kB and elevating Nrf2, reduces brain edema and neurological dysfunction after cerebral I/R

BACKGROUND

Oxidation, inflammation, and apoptosis are three critical factors for the pathogenic mechanism of cerebral ischemia/reperfusion (I/R) injury. Curcumin exhibits substantial biological properties via anti-oxidation, anti-inflammation and anti-apoptotic effects; however, the molecular mechanism underlying the effects of curcumin against cerebral I/R injury remains unclear.

OBJECTIVE

To investigate the effects of curcumin on cerebral I/R injury associated with water content, infarction volume, and the expression of nuclear factor-kappa-B (NF-κB) and nuclear factor-erythroid-related factor-2 (Nrf2).

METHODS

Middle cerebral artery occlusion (MCAO, 1-hour occlusion and 24-hour reperfusion) was performed in male Wistar rats (n=64) as a cerebral I/R injury model. In the MCAO+CUR group, the rats were administered curcumin (300mg/kg BW, i.p.) at 30min after occlusion. The same surgical procedures were performed in SHAM rats without MCAO occlusion. At 24h post-operation, the parameters, including neurological deficit scores, blood brain barrier (BBB) disruption, water content, and infarction volume, were determined. Brain tissue NF-κB and Nrf2 expression levels were assayed through immunohistochemistry.

RESULTS

Compared with the SHAM group, BBB disruption, neurological deficit, and increased brain water content and infarction volume were markedly demonstrated in the MCAO group. NF-κB expression was enhanced in the MCAO group. However, in the MCAO+CUR group, the upregulation of Nrf2, an anti-oxidation related protein, was consistent with a significant decline in the water content, infarction volume, and NF-κB expression.

CONCLUSION

The protective effects of curcumin against cerebral I/R injury reflect anti-oxidation, anti-inflammation and anti-apoptotic activities, resulting in the elevation of Nrf2 and down-regulation of NF-κB.

A review on mitochondrial restorative mechanism of antioxidants in Alzheimer's disease and other neurological conditions

Neurodegenerative diseases are intricate in nature because of the involvement of the multiple pathophysiological events including mitochondrial dysfunction, neuroinflammation and oxidative stress. Alzheimer’s disease (AD) is a neurodegenerative disease explained by extracellular amyloid β deposits, intracellular neurofibrillary tangles and mitochondrial dysfunction. Increasing evidence has indicated that mitochondrial dysfunction displays significant role in the pathophysiological processes of AD. Mitochondrial dysfunction involves alterations in mitochondrial respiratory enzyme complex activities, oxidative stress, opening of permeability transition pore, and enhanced apoptosis. Various bioenergetics and antioxidants have been tried or under different investigational phase against AD and other neurodegenerative disorders (Parkinson’s disease, Huntington’s disease, and Amyotrophic lateral sclerosis) because of their complex and multiple site of action. These mitochondrial-targeting bioenergetics and antioxidant compounds such as coenzyme Q10, idebenone, creatine, mitoQ, mitovitE, MitoTEMPOL, latrepirdine, methylene blue, triterpenoids, SS peptides, curcumin, Ginkgo biloba, and omega-3 polyunsaturated fatty acids with potential efficacy in AD have been identified. Present review is intent to discuss mitochondrial restorative mechanisms of these bioenergetics and antioxidants as a potential alternative drug strategy for effective management of AD.

Common and unique mechanisms of Chinese herbal remedies on ischemic stroke mice revealed by transcriptome analyses

ETHNOPHARMACOLOGICAL RELEVANCE

Four traditional Chinese herbal remedies (CHR) including Buyang Huanwu decoction (BHD), Xuefu Zhuyu decoction (XZD), Tianma Gouteng decoction (TGD) and Shengyu decoction (SYD) are popular used in treating brain-related dysfunction clinically with different syndrome/pattern based on traditional Chinese medicine (TCM) principles, yet their neuroprotective mechanisms are still unclear.

MATERIALS AND METHODS

Mice were subjected to an acute ischemic stroke to examine the efficacy and molecular mechanisms of action underlying these CHR.

RESULTS

CHR treatment significantly enhanced the survival rate of stroke mice, with BHD being the most effective CHR. All CHR were superior to recombinant tissue-type plasminogen activator (rt-PA) treatment in successfully ameliorating brain function, infarction, and neurological deficits in stroke mice that also paralleled to improvements in blood-brain barrier damage, inflammation, apoptosis, and neurogenesis. Transcriptome analyses reveals that a total of 774 ischemia-induced probe sets were significantly modulated by four CHR, including 52 commonly upregulated genes and 54 commonly downregulated ones. Among them, activation of neurogenesis-associated signaling pathways and down-regulating inflammation and apoptosis pathways are key common mechanisms in ischemic stroke protection by all CHR. Besides, levels of plasma CX3CL1 and S100a9 in patients could be used as biomarkers for therapeutic evaluation before functional recovery could be observed.

CONCLUSION

Our results suggest that using CHR, a combinatory cocktail therapy, is a better way than rt-PA for treating cerebral ischemic-associated diseases through modulating a common as well as a specific group of genes/pathways that may partially explain the syndrome differentiation and treatment principle in TCM.

Curcumin boosts DHA in the brain: Implications for the prevention of anxiety disorders

Dietary deficiency of docosahexaenoic acid (C22:6 n-3; DHA) is linked to the neuropathology of several cognitive disorders, including anxiety. DHA, which is essential for brain development and protection, is primarily obtained through the diet or synthesized from dietary precursors, however the conversion efficiency is low. Curcumin (diferuloylmethane), which is a principal component of the spice turmeric, complements the action of DHA in the brain, and this study was performed to determine molecular mechanisms involved. We report that curcumin enhances the synthesis of DHA from its precursor, α-linolenic acid (C18:3 n-3; ALA) and elevates levels of enzymes involved in the synthesis of DHA such as FADS2 and elongase 2 in both liver and brain tissues. Furthermore, in vivo treatment with curcumin and ALA reduced anxiety-like behavior in rodents. Taken together, these data suggest that curcumin enhances DHA synthesis, resulting in elevated brain DHA content. These findings have important implications for human health and the prevention of cognitive disease, particularly for populations eating a plant-based diet or who do not consume fish, a primary source of DHA, since DHA is essential for brain function and its deficiency is implicated in many types of neurological disorders.

4-((1E)-2-(5-(4-hydroxy-3-methoxystyryl-)-1-phenyl-1H-pyrazoyl-3-yl) vinyl)-2-methoxy-phenol) (CNB-001) Does Not Regulate Human Recombinant Protein-Tyrosine Phosphatase1B (PTP1B) Activity in vitro

Protein-Tyrosine Phosphatase1B (PTP1B) is a negative regulator of the insulin signaling pathway and is a potential therapeutic target for treatment of type 2 diabetes, cardiovascular disease, metabolic syndrome and cancer. It has been postulated that CNB-001 [4-((1E)-2-(5-(4-hydroxy-3-methoxystyryl-)-1-phenyl-1H-pyrazoyl-3-yl) vinyl)-2-methoxy-phenol)] may regulate PTP1B activity suggested by a computer-based active site docking recognition model. This possibility was studied using a human recombinant PTP1B assay, and a phospho-peptide fragment of the insulin receptor β subunit domain (IR5). The positive control, suramin, inhibited PTP1B with an IC50 (half minimal (50%) inhibitory concentration) value of 16.34 µM; CNB-001 did not affect enzyme activity across the range of 1nM-0.1mM. This study suggests that PTP1B inhibition is not involved in the beneficial effects of CNB-001 in obese type 2 diabetic mice.

Unique mechanisms of sheng yu decoction ( shèng yù tang) on ischemic stroke mice revealed by an integrated neurofunctional and transcriptome analysis

Sheng Yu Decoction ( Shèng Yù Tang; SYD) is a popular traditional Chinese medicine (TCM) remedy used in treating cardiovascular and brain-related dysfunction clinically; yet, its neuroprotective mechanisms are still unclear. Here, mice were subjected to an acute ischemic stroke to examine the efficacy and mechanisms of action of SYD by an integrated neurofunctional and transcriptome analysis. More than 80% of the mice died within 2 days after ischemic stroke with vehicle treatment. Treatments with SYD (1.0 g/kg, twice daily, orally or p.o.) and recombinant thrombolytic tissue plasminogen activator (rt-PA; 10 mg/kg, once daily, intravenously or i.v.) both significantly extended the lifespan as compared to that of the vehicle-treated stroke group. SYD successfully restored brain function, ameliorated cerebral infarction and oxidative stress, and significantly improved neurological deficits in mice with stroke. Molecular impact of SYD by a genome-wide transcriptome analysis using brains from stroke mice showed a total of 162 out of 2081 ischemia-induced probe sets were significantly influenced by SYD. Mining the functional modules and genetic networks of these 162 genes revealed a significant upregulation of neuroprotective genes in Wnt receptor signaling pathway (3 genes) and regulation of cell communication (7 genes) and downregulation of destructive genes in response to stress (13 genes) and in the induction of inflammation (5 genes), cytokine production (4 genes), angiogenesis (3 genes), vasculature (6 genes) and blood vessel (5 genes) development, wound healing (7 genes), defense response (7 genes), chemotaxis (4 genes), immune response (7 genes), antigen processing and presenting (3 genes), and leukocyte-mediated cytotoxicity (2 genes) by SYD. Our results suggest that SYD could protect mice against ischemic stroke primarily through significantly downregulating the damaging genes involved in stress, inflammation, angiogenesis, blood vessel formation, immune responses, and wound healing, as well as upregulating the genes mediating neurogenesis and cell communication, which make SYD beneficial for treating ischemic stroke.

Therapeutic effects of traditional herbal medicine on cerebral ischemia: a perspective of vascular protection

Although many agents for acute ischemic stroke treatment have been developed from extensive preclinical studies, most have failed in clinical trials. As a result, researchers are seeking other methods or agents based on previous studies. Among the various prospective approaches, vascular protection might be the key for development of therapeutic agents for stroke and for improvements in the efficacy and safety of conventional therapies. Traditional medicines in Asian countries are based on clinical experiences and literature accumulated over thousands of years. To date, many studies have used traditional herbal medicines to prove or develop new agents based on stroke treatments mentioned in traditional medicinal theory or other clinical data. In the current review, we describe the vascular factors related to ischemic brain damage and the herbal medicines that impact these factors, including Salviae Miltiorrhizae Radix, Notoginseng Radix, and Curcumae Rhizoma, based on scientific reports and traditional medical theory. Further, we point out the problems associated with herbal medicines in stroke research and propose better methodologies to address these problems.

The effect of curcumin on oxaliplatin and cisplatin neurotoxicity in rats: some behavioral, biochemical, and histopathological studies

Cisplatin is commonly used against several solid tumors, and oxaliplatin is an effective cytotoxic drug used in colorectal cancer. A major clinical issue affecting 10-40 % of patients treated with cisplatin or oxaliplatin is severe peripheral neuropathy causing sensory, motor, and autonomic dysfunction, with symptoms including cold sensitivity and neuropathic pain. The biochemical basis of the neurotoxicity is uncertain, but is associated with oxidative stress. Curcumin (a natural phenolic yellow pigment) has strong antioxidant, anticancer, and anti-inflammatory actions. Here we report the possible protective effect of curcumin on some cisplatin- and oxaliplatin-induced behavioral, biochemical, and histopathological alterations in rats. Twenty-four hours after the end of treatments some motor and behavioral tests (motor activity, thermal and mechanical nociception, and neuromuscular coordination) were conducted, followed by measuring plasma neurotensin platinum concentration in the sciatic nerve, and studying the histopathology of the sciatic nerve. Oxaliplatin (4 mg/kg) and cisplatin (2 mg/kg) [each given twice weekly, in a total of nine intraperitoneal injections over 4.5 weeks] significantly increased plasma neurotensin concentration, caused specific damage in the histology of the sciatic nerve and produced variable effects in the motor and behavioral tests. Oral curcumin (10 mg/kg, 4 days before the platinum drug, and thereafter, concomitantly with it for 4.5 weeks) reversed the alterations in the plasma neurotensin and sciatic nerve platinum concentrations, and markedly improved sciatic nerve histology in the platinum-treated rats. Larger experiments using a wider dose range of oxaliplatin, cisplatin, and curcumin are required to fully elucidate the possible protective role of curcumin in platinum-induced neurotoxicity.

RIGOR guidelines: escalating STAIR and STEPS for effective translational research

Stroke continues to be a serious and significant health problem in the USA and worldwide. This article will emphasize the need for good laboratory practices, transparent scientific reporting, and the use of translational research models representative of the disease state to develop effective treatments. This will allow for the testing and development of new innovative strategies so that efficacious therapies can be developed to treat ischemic and hemorrhagic stroke. This article recommends guidelines for effective translational research, most importantly, the need for study blinding, study group randomization, power analysis, accurate statistical analysis, and a conflict of interest statement. Additional guidelines to ensure reproducibility of results and confirmation of efficacy in multiple species are discussed.

Neuroprotective effect of curcumin on spinal cord in rabbit model with ischemia/reperfusion

BACKGROUND

Ischemic/reperfusion (I/R) injury of the spinal cord is a serious complication that can result from thoracoabdominal aortic surgery.

OBJECTIVE

To investigate the neuroprotective effect of curcumin against I/R injury in a rabbit model.

METHODS

A total of 36 rabbits were randomly divided into three groups: sham, I/R, and curcumin-treated group. Rabbits were subject to 30-min aortic occlusion to induce transient spinal cord ischemia. Neurological function was observed after reperfusion and spinal cord segment (L3-L5) was collected for histopathological evaluation. Malondialdehyde (MDA) and total superoxide dismutase (SOD) activity were also assayed.

RESULTS

Rabbits in I/R group were induced to paraplegia. While after 48-hour treatment, compared with I/R group, curcumin significantly improved neurological function, reduced cell apoptosis and MDA levels as well as increased SOD activity (P < 0.05).

CONCLUSIONS

The results suggest that curcumin, at least in an animal model, can attenuate transient spinal cord ischemic injury potentially via reducing oxidative damage, which may provide a novel approach in the treatment of spinal cord ischemic injury.

Dietary therapy to promote neuroprotection in chronic spinal cord injury

OBJECT

The pathogenesis of cervical spondylotic myelopathy (CSM) is related to both primary mechanical and secondary biological injury. The authors of this study explored a novel, noninvasive method of promoting neuroprotection in myelopathy by using curcumin to minimize oxidative cellular injury and the capacity of omega-3 fatty acids to support membrane structure and improve neurotransmission.

METHODS

An animal model of CSM was created using a nonresorbable expandable polymer placed in the thoracic epidural space, which induced delayed myelopathy. Animals that underwent placement of the expandable polymer were exposed to either a diet rich in docosahexaenoic acid and curcumin (DHA-Cur) or a standard Western diet (WD). Twenty-seven animals underwent serial gait testing, and spinal cord molecular assessments were performed after the 6-week study period.

RESULTS

At the conclusion of the study period, gait analysis revealed significantly worse function in the WD group than in the DHA-Cur group. Levels of brain-derived neurotrophic factor (BDNF), syntaxin-3, and 4-hydroxynonenal (4-HNE) were measured in the thoracic region affected by compression and lumbar enlargement. Results showed that BDNF levels in the DHA-Cur group were not significantly different from those in the intact animals but were significantly greater than in the WD group. Significantly higher lumbar enlargement syntaxin-3 in the DHA-Cur animals combined with a reduction in lipid peroxidation (4-HNE) indicated a possible healing effect on the plasma membrane.

CONCLUSIONS

Data in this study demonstrated that DHA-Cur can promote spinal cord neuroprotection and neutralize the clinical and biochemical effects of myelopathy.

Curcumin--from molecule to biological function

Turmeric is traditionally used as a spice and coloring in foods. It is an important ingredient in curry and gives curry powder its characteristic yellow color. As a consequence of its intense yellow color, turmeric, or curcumin (food additive E100), is used as a food coloring (e.g. mustard). Turmeric contains the curcuminoids curcumin, demethoxycurcumin, and bisdemethoxycurcumin. Recently, the health properties (neuroprotection, chemo-, and cancer prevention) of curcuminoids have gained increasing attention. Curcuminoids induce endogenous antioxidant defense mechanisms in the organism and have anti-inflammatory activity. Curcuminoids influence gene expression as well as epigenetic mechanisms. Synthetic curcumin analogues also exhibit biological activity. This Review describes the development of curcumin from a "traditional" spice and food coloring to a "modern" biological regulator.

Melatonin ameliorates neural function by promoting endogenous neurogenesis through the MT2 melatonin receptor in ischemic-stroke mice

Melatonin has many protective effects against ischemic stroke, but the underlying neuroprotective mechanisms are not fully understood. Our aim was to explore the relationship between melatonin's neuroprotective effects and activation of the MT2 melatonin receptor in a murine ischemic-stroke model. Male ICR mice were subjected to a transient middle cerebral ischemic/reperfusional injury, and melatonin (5 and 10 mg/kg, ip) was administrated once daily starting 2 h after ischemia. More than 80% of the mice died within 5 days after stroke without treatment. Melatonin treatment significantly improved the survival rates and neural functioning with modestly prolonged life span of the stroke mice by preserving blood-brain barrier (BBB) integrity via a reduction in the enormous amount of stroke-induced free radical production and significant gp91(phox) cell infiltration. These protective effects of melatonin were reversed by pretreatment with MT2 melatonin receptor antagonists (4-phenyl-2-propionamidotetralin (4P-PDOT) and luzindole). Moreover, treatment with melatonin after stroke dramatically enhanced endogenous neurogenesis (doublecortin positive) and cell proliferation (ki67 positive) in the peri-infarct regions. Most ki67-positive cells were nestin-positive and NG2-positive neural stem/progenitor cells that coexpressed two neurodevelopmental proteins (adam11 and adamts20) and the MT2 melatonin receptor. RT-PCR revealed that the gene expression levels of doublecortin, ki67, adamts20, and adam11 are markedly reduced by stroke, but are restored by melatonin treatment; furthermore, pretreatment with 4P-PDOT and luzindole antagonized melatonin's restorative effect. Our results support the hypothesis that melatonin is able to protect mice against stroke by activating MT2 melatonin receptors, which reduces oxidative/inflammatory stress. This results in the preservation of BBB integrity and enhances endogenous neurogenesis by upregulating neurodevelopmental gene/protein expression.

Neuroprotection and sensorimotor functional improvement by curcumin after intracerebral hemorrhage in mice

Previous studies revealed that curcumin is neuroprotective in diseases of the central nervous system such as cerebral ischemia and traumatic brain injury. However, the effect of curcumin on intracerebral hemorrhage remains unclear. We, therefore, investigated the pre-clinical effect of curcumin treatment on neurological outcomes following intracerebral hemorrhage, using a mouse model. Intracerebral hemorrhage was induced by autologous blood injection into the right basal ganglia. Curcumin (150 mg/kg) was administered 15 min after intracerebral hemorrhage. Grid walk and neurological scores were evaluated at 1, 3, 7, and 14 days post-injury. Mice were killed at 24 h or 28 days following injury, for histological examination. Evans Blue and water content in the ipsilateral and contralateral hemispheres were measured to evaluate the extent of blood-brain barrier disruption and brain edema. Zonula occludens-1 was detected by immunostaining. In situ zymography was used to measure the localization and focal enzymatic activity of matrix metalloproteinase. Our results demonstrated that curcumin reduced brain edema, measured by alleviated water content and Evans Blue leakage at 24 h (p<0.05). Lateral ventricle measurements indicated that curcumin reduced brain tissue loss in the ipsilateral hemisphere (p<0.05). The same dose of curcumin also significantly attenuated neurological deficits at 1 and 3 days of intracerebral hemorrhage (p<0.05). Immunostaining showed that tight junction continuity around the hematoma was better sustained in curcumin-treated mice than in vehicle-treated mice. At 24 h, the number of matrix metalloproteinase-positive cells was significantly reduced by curcumin (p<0.05). Our study suggests that curcumin ameliorates intracerebral hemorrhage damage by preventing matrix metalloproteinase-mediated blood-brain barrier damage and brain edema, which might provide therapeutic potential for intracerebral hemorrhage.

Deciphering the neuroprotective mechanisms of Bu-yang Huan-wu decoction by an integrative neurofunctional and genomic approach in ischemic stroke mice

ETHNOPHARMACOLOGICAL RELEVANCE

Bu-yang Huan-wu decoction (BHD) is a famous traditional Chinese medicine formula that has been used clinically in Asia to treat stroke-induced disability for centuries, but the underlying neuroprotective mechanisms are not fully understood.

AIM OF THE STUDY

In this study, we aim to investigate the mechanisms of action using an integrative neurofunctional and broad genomics approach.

MATERIALS AND METHODS

Male ICR mice were subjected to an acute ischemic stroke by inducing a middle cerebral ischemic/reperfusion (CI/R) injury. To examine whether BHD could extend the lifespan of mice with a stroke, we used oral administration of BHD (0.5 and 1.0g/kg) twice daily starting from 2h after ischemia and compared this with vehicle control treatments, recombinant tissue-type plasminogen activator (rt-PA, 10mg/kg, i.v.), and MK-801 (0.2mg/kg, i.p.). An integrative neurofunctional and genomic approach was performed to elucidate the underlying molecular mechanisms of BHD.

RESULTS

More than 80% of the mice died within 2 days after stroke induction in the vehicle control treatment group. However, the survival rates and life-spans of mice treated with BHD, rt-PA and MK-801 were significantly enhanced as compared to the vehicle-treated CI/R group in all three cases. Mice treated with BHD (1.0g/kg) showed the greatest protective effect across all groups. BHD successfully restored brain function, ameliorated the cerebral infarction, and significantly improved the neurological deficits of the mice with a stroke. BHD also reduced inflammation, oxidative stress, and apoptosis, as well as improved neurogenesis. The molecular impacts of BHD were assessed by genome-wide transcriptome analysis using brains from the CI/R mice. The results showed a total of 377 ischemia-induced probe-sets that were significantly influenced by BHD including 93 probe-sets that were commonly more abundant in BHD-treated and sham mice, and another 284 ischemia-induced probe sets that were suppressed by BHD. Mining the functional modules and genetic networks of these 377 genes revealed a significant upregulation of neuroprotective genes associated with neurogenesis (6 genes) and nervous system development (9 genes), and a significant down-regulation of destructive genes associated with the induction of inflammation (14 genes), apoptosis (15 genes), angiogenesis (11 genes) and blood coagulation (7 genes) by BHD.

CONCLUSIONS

Our results suggested that BHD is able to protect mice against stroke and extend lifespan primarily through a significant down-regulation of genes involved in inflammation, apoptosis, angiogenesis and blood coagulation, as well as an up-regulation of genes mediating neurogenesis and nervous system development. The changes in expression after treatment with BHD are beneficial after ischemic stroke.

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

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