Pharmacological benefits of agomelatine and vanillin in experimental model of Huntington's disease

Ameliorative effects of vanillin against pentylenetetrazole-induced epilepsy and associated memory loss in mice: The role of Nrf2/HO-1/NQO1 and HMGB1/RAGE/TLR4/NFκB pathways

BACKGROUND

Epilepsy is a severe neurological disorder associated with substantial morbidity and mortality. Vanillin (Van) is a natural phenolic aldehyde with beneficial pharmacological properties. This study investigated the neuroprotective effects of Van in epilepsy and elucidated its mechanism of action.

METHODS

Swiss albino mice were divided into the following five groups: "normal group", 0.9 % saline; "pentylenetetrazole (PTZ) group", intraperitoneal administration of 35 mg/kg PTZ on alternate days up to 42 days; and "PTZ + Van 20", "PTZ + Van 40", and "PTZ + sodium valproate (Val)" groups received PTZ injections in conjunction withVan 20 mg, Van 40 mg/kg, and Val 300 mg/kg, respectively. Behavioural tests and hippocampal histopathological analysis were performed in all groups. The Nrf2/HO-1/NQO1 and HMGB1/RAGE/TLR4/NFκB pathways, oxidative stress, neuro-inflammation, and apoptotic markers were analysed. Furthermore, brain acetylcholinesterase (AChE) activity and levels of dopamine (DA), gamma-aminobutyric acid GABA, and serotonin 5-HT were assessed.

RESULTS

Van prolonged seizure manifestations and improved electroencephalogram (EEG)criteriain conjunction with 100 mg/kg PTZ once daily. Van administration increased Nrf2/HO-1/NQO1 levels, with subsequent attenuation of malondialdehyde (MDA) and nitric oxide (NO) levels with elevated glutathione (GSH) levels and intensified superoxide dismutase (SOD) and catalase activities. Van reduced the gene and protein expression of HMGB1/RAGE/TLR4/NFκB and decreased the levels of inflammatory and apoptotic markers. In addition, Van reduced AChE activity, and elevated glial fibrillary acidic proteins (GFAP) increased neurotransmitter and brain-derived neurotrophic factors (BDNF).

CONCLUSION

By increasing Nrf2/HO-1/NQO1 levels and downregulating the HMGB1/RAGE/TLR4/ NFκB pathway, Van offered protection in PTZ-kindled mice with subsequent attenuation in lipid peroxidation, upregulation in antioxidant enzyme activities, and reduction in inflammation and apoptosis.

TRPV1 modulated NLRP3 inflammasome activation via calcium in experimental subarachnoid hemorrhage

Neuroinflammation plays a key role in early brain injury (EBI) of subarachnoid hemorrhage (SAH), and NLRP3 inflammasome plays an important role in the development of neuroinflammation after SAH, but the mechanism of NLRP3 inflammasome activation after SAH is still unclear. TRPV1 is a non-selective calcium channel that is involved in the pathology of neuroinflammation, but its role in SAH has not been revealed. Our study showed that TRPV1 was significantly upregulated after SAH and was predominantly expressed in microglia/macrophages. Antagonism of TRPV1 was effective in ameliorating neurological impairment, brain edema, neuronal damage, and reducing the inflammatory response (evidenced by reducing the number of CD16/32 positive microglia/macrophages, inhibiting the expression of CD16, CD32, CD86, IL-1b, TNF-a and blocking NLRP3 inflammasome activation). However, this effect can be abolished by NLRP3 inflammasome antagonist MCC950. In vitro experiment confirmed that TRPV1 activated NLRP3 inflammasome by increasing intracellular calcium levels. In conclusion, TRPV1 mediates EBI after SAH via calcium/NLRP3, and TRPV1 is a potential therapeutic target after SAH.

Beyond Conventional Therapies: Molecular Dynamics of Alzheimer's Treatment through CLOCK/BMAL1 Interactions

BACKGROUND

Alzheimer's Disease (AD) represents a neurodegenerative disorder characterized by cognitive and behavioral impairments significantly hindering social and occupational functioning. Melatonin, a hormone pivotal in regulating the body's intrinsic circadian rhythm, also acts as a catalyst in the breakdown of beta-amyloid deposits, offering a promising therapeutic approach for AD. The upregulation of Brain and Muscle ARNT-Like 1 (Bmal1) gene expression, stimulated by melatonin, emerges as a potential contributor to AD intervention. Current pharmacological interventions, such as FDA-approved cholinesterase inhibitors and the recently authorized monoclonal antibody, Lecanemab, are utilized in AD management. However, the connection between these medications and Bmal1 remains insufficiently explored.

OBJECTIVE

This study aims to investigate the molecular effects of FDA-endorsed drugs on the CLOCK: Bmal1 dimer. Furthermore, considering the interactions between melatonin and Bmal1, this research explores the potential synergistic efficacy of combining these pharmaceutical agents with melatonin for AD treatment.

METHODS

Using molecular docking and MM/PBSA methodologies, this research determines the binding affinities of drugs within the Bmal1 binding site, constructing interaction profiles.

RESULTS

The findings reveal that, among FDA-approved drugs, galanthamine and donepezil demonstrate notably similar binding energy values to melatonin, interacting within the Bmal1 binding site through analogous amino acid residues and functional groups.

CONCLUSION

A novel therapeutic approach emerges, suggesting the combination of melatonin with Lecanemab as a monoclonal antibody therapy. Importantly, prior research has not explored the effects of FDA-approved drugs on Bmal1 expression or their potential for synergistic effects.

Impact of TRPV1 on Pathogenesis and Therapy of Neurodegenerative Diseases

Transient receptor potential vanilloid 1 (TRPV1) is a transmembrane and non-selective cation channel protein, which can be activated by various physical and chemical stimuli. Recent studies have shown the strong pathogenetic associations of TRPV1 with neurodegenerative diseases (NDs), in particular Alzheimer's disease (AD), Parkinson's disease (PD) and multiple sclerosis (MS) via regulating neuroinflammation. Therapeutic effects of TRPV1 agonists and antagonists on the treatment of AD and PD in animal models also are emerging. We here summarize the current understanding of TRPV1's effects and its agonists and antagonists as a therapeutic means in neurodegenerative diseases, and highlight future treatment strategies using natural TRPV1 agonists. Developing new targets and applying natural products are becoming a promising direction in the treatment of chronic disorders, especially neurodegenerative diseases.

Vanillin attenuates CdCl2-induced cytotoxicity in isolated human erythrocytes

Cadmium is a toxic heavy metal with no physiological role in the human body. Cadmium has high mobility due to its widespread industrial use, with no safe and effective therapeutic management. Cadmium toxicity manifests by increasing oxidative stress in target cells. We have explored the potential role of vanillin, a plant phenolic aldehyde and antioxidant, in mitigating cadmium chloride (CdCl2) induced hemotoxicity using isolated human erythrocytes. CdCl2 was added to erythrocytes, in the absence and presence of vanillin. Incubation of erythrocytes with CdCl2 alone inhibited methemoglobin reductase and enhanced methemoglobin level. Heme degradation and release of free iron (Fe2+), along with protein and membrane lipid oxidation, were also increased. A CdCl2-induced enhancement in reactive oxygen and nitrogen species was also seen, lowering the overall antioxidant power of cells. However, pre-incubation of erythrocytes with vanillin resulted in significant decreased generation of reactive species and prevented heme degradation and heme oxidation. Vanillin augmented the erythrocyte antioxidant capacity and reinstated the activities of major antioxidant, plasma membrane-bound and glucose metabolism enzymes. Scanning electron microscopy showed that CdCl2 treatment led to the formation of echinocytes which was prevented by vanillin. In all cases, no harmful effects of vanillin alone were seen. Thus, vanillin alleviates the toxicity of cadmium and can be potentially employed as a chemoprotectant against the damaging effects of this heavy metal.

Behavioral and biochemical investigations to explore the efficacy of quercetin and folacin in experimental diabetes induced vascular endothelium dysfunction and associated dementia in rats

OBJECTIVES

Vascular dementia (VaD), being strongly associated with metabolic conditions is a major health concern around the world. Diabetes is a major risk factor for the development of VaD. This study investigates the efficacy of quercetin and folacin in diabetes induced vascular endothelium dysfunction and related dementia.

METHODS

Single dose streptozotocin (STZ) (50 mg/kg i.p) was administered to albino Wistar rats (male, 200-250 g) by dissolving in citrate buffer. Morris water maze (MWM) and attentional set shifting tests were used to assess the spatial learning, memory, reversal learning, and executive functioning in animals. Body weight, serum glucose, serum nitrite/nitrate, vascular endothelial function, aortic superoxide anion, brains' oxidative markers (thiobarbituric acid reactive species-TBARS, reduced glutathione-GSH, superoxide dismutase-SOD, and catalase-CAT), mitochondrial enzyme complex (I, II, and IV), inflammatory markers (interleukin-IL-6, IL-10, tumor necrosis factor-TNF-α, and myeloperoxidase-MPO), and acetylcholinesterase activity-AChE were also assessed. Quercetin (30 mg kg-1/60 mg kg-1) and folacin (30 mg kg-1/60 mg kg-1) were used as the treatment drugs. Donepezil (0.5 mg kg-1) was used as a positive control.

RESULTS

STZ administered rats showed reduction in learning, memory, reversal learning, executive functioning, impairment in endothelial function, increase in brains' oxidative stress; inflammation; AChE activity, and decrease in mitochondrial complex (I, II, and IV) activity. Administration of quercetin and folacin in two different doses, significantly attenuated the STZ induced diabetes induced impairments in the behavioral, endothelial, and biochemical parameters.

CONCLUSIONS

STZ administration caused diabetes and VaD which was attenuated by the administration of quercetin and folacin. Therefore, these agents may be studied further for the assessment of their full potential in diabetes induced VaD conditions.

A Review on Natural Antioxidants for Their Role in the Treatment of Parkinson's Disease

The neurodegenerative condition known as Parkinson's disease (PD) is brought on by the depletion of dopaminergic neurons in the basal ganglia, which is the brain region that controls body movement. PD occurs due to many factors, from which one of the acknowledged effects of oxidative stress is pathogenic pathways that play a role in the development of Parkinson's disease. Antioxidants, including flavonoids, vitamins E and C, and polyphenolic substances, help to reduce the oxidative stress brought on by free radicals. Consequently, this lowers the risk of neurodegenerative disorders in the long term. Although there is currently no cure for neurodegenerative illnesses, these conditions can be controlled. The treatment of this disease lessens its symptoms, which helps to preserve the patient's quality of life. Therefore, the use of naturally occurring antioxidants, such as polyphenols, which may be obtained through food or nutritional supplements and have a variety of positive effects, has emerged as an appealing alternative management strategy. This article will examine the extent of knowledge about antioxidants in the treatment of neurodegenerative illnesses, as well as future directions for research. Additionally, an evaluation of the value of antioxidants as neuroprotective agents will be provided.

Overview of the Role of Vanillin in Neurodegenerative Diseases and Neuropathophysiological Conditions

Nowadays, bioactive natural products play key roles in drug development due to their safety profile and strong antioxidant power. Vanillin is a natural phenolic compound found in several vanilla beans and widely used for food, cosmetic, and pharmaceutical products. Besides its industrial applications, vanillin possesses several beneficial effects for human health, such as antioxidant activity in addition to anti-inflammatory, anti-mutagenic, anti-metastatic, and anti-depressant properties. Moreover, vanillin exhibits neuroprotective effects on multiple neurological disorders and neuropathophysiological conditions. This study reviews the mechanisms of action by which vanillin prevents neuroinflammation and neurodegeneration in vitro and in vivo systems, in order to provide the latest views on the beneficial properties of this molecule in chronic neurodegenerative diseases and neuropathophysiological conditions.

Ameliorative effect of vanillin on scopolamine-induced dementia-like cognitive impairment in a mouse model

BACKGROUND

Alzheimer's disease (AD) is the most common form of dementia, which is among the top five causes of death in the United States. It is a neurodegenerative disorder that causes permanent loss of memory and cognition. The current pharmacotherapy for AD is based on providing symptomatic relief only and has many side effects. There is a need for a safer, disease-modifying drug for the treatment of AD.

EXPERIMENTAL APPROACH

The PASS online software was used to screen phytoconstituents based on their predicted effects on various AD-related targets. Vanillin was selected as the compound of interest, as it has not been researched elaborately on any animal model of AD. The acetylcholinesterase inhibitory activity of vanillin was established in vitro. Thereafter, ameliorative effect of vanillin was evaluated using the exteroceptive memory model in scopolamine-induced cognitive impairment mice model.

RESULTS

Vanillin showed an acetylcholinesterase inhibitory activity in vitro, and the IC50 value was calculated to be 0.033 mM. Vanillin significantly reversed the memory and behavioral deficits caused by scopolamine as demonstrated by significant improvement in memory in negative reinforcement, elevated plus maze, and spatial learning paradigms. Vanillin also proved to have a nootropic effect. Also, vanillin proved to have significantly better antioxidant and acetylcholinesterase inhibitory effects in vivo than donepezil hydrochloride. The potential anti-AD activity of vanillin was also confirmed by the reduction in IL-6 levels and TNF-α levels.

CONCLUSION

Our results suggest that vanillin is a safe and effective natural drug candidate having a great potential for the treatment of AD. However, more research is required to evaluate its effect on A beta plaques and Tau neurofibrillary tangles in vivo.

Metabolic Engineering of Rice Cells with Vanillin Synthase Gene (VpVAN) to Produce Vanillin

Vanillin production by metabolic engineering of proprietary microbial strains has gained impetus due to increasing consumer demand for naturally derived products. Here, we demonstrate the use of rice cell cultures metabolically engineered with vanillin synthase gene (VpVAN) as a plant-based alternative to microbial vanillin production systems. VpVAN catalyzes the signature step to convert ferulic acid into vanillin in Vanilla planifolia. As ferulic acid is a phenylpropanoid pathway intermediate in plant cells, rice calli cells are ideal platform for in vivo vanillin synthesis due to the availability of its precursor. In this study, rice calli derived from embryonic rice cells were metabolically engineered with a codon-optimized VpVAN gene using Agrobacterium-mediated transformation. The putative transformants were selected based on their proliferation on herbicide-supplemented N6D medium. Expression of the transgenes were confirmed through a β-glucuronidase (GUS) reporter assay and polymerase chain reaction (PCR) analysis provided evidence of genetic transformation. The semiquantitative RT-PCR and real-time (RT)-qPCR revealed expression of VpVAN in six transgenic calli lines. High-performance liquid chromatography identified the biosynthesis of vanillin in transgenic calli lines, with the highest yielding line producing 544.72 (± 102.50) μg of vanillin^-g fresh calli. This work serves as a proof-of-concept to produce vanillin using metabolically engineered rice cell cultures.

Efficacy of Ulinastatin and Sulforaphane Alone or in Combination in Rat Model of Streptozotocin Diabetes Induced Vascular Dementia

Objective

Vascular Dementia (VaD), is associated with metabolic conditions. Diabetes is a major risk factor for the development of VaD. This study investigates the efficacy of ulinastatin (UTI) and sulforaphane (SUL) in streptozotocin (STZ)-diabetes induced vascular endothelium dysfunction and related dementia.

Methods

Single dose STZ (50 mg/kg i.p.) was administered to Albino Wistar rats (male, 200−250 g). Morris water maze and attentional set shifting tests were used to assess the spatial learning, memory, reversal learning, and executive functioning in animals. Body weight, serum glucose, serum nitrite/nitrate, vascular endothelial function, aortic superoxide anion, brains’ oxidative markers (thiobarbituric acid reactive species-TBARS, reduced glutathione-GSH, superoxide dismutase-SOD, and catalase-CAT), inflammatory markers (IL-6, IL-10, TNF-a, and myeloperoxidase-MPO), acetylcholinesterase activity-AChE, blood brain barrier (BBB) permeability and histopathological changes were also assessed. UTI (10,000 U/kg) and SUL (25 mg/kg) were used alone as well as in combination, as the treatment drugs. Donepezil (0.5 mg/kg) was used as a positive control.

Results

STZ-administered rats showed reduction in body weight, learning, memory, reversal learning, executive functioning, impairment in endothelial function, BBB permeability, increase in serum glucose, brains’ oxidative stress, inflammation, AChE-activity, BBB permeability and histopathological changes. Administration of UTI and SUL alone as well as in combination, significantly and dose dependently attenuated the STZ-diabetes-induced impairments in the behavioral, endothelial, and biochemical parameters.

Conclusion

STZ administration caused diabetes and VaD which was attenuated by the administration of UTI and SUL. Therefore, these agents may be studied further for the assessment of their full potential in diabetes induced VaD.

Synthesis of new 1,4-disubstituted 1,2,3-triazoles using the CuAAC reaction and determination of their antioxidant activities

This study describes the synthesis and antioxidant activity of new 1,4-disubstituted 1,2,3-triazoles. These compounds were generated semi-synthetically using the Cu(I)-catalysed azide-alkyne cycloaddition (CuAAC) reaction between ethyl 2-azidoacetate and terminal acetylenes derived from the natural products carvacrol, eugenol, isovanillin, thymol and vanillin. The products were obtained at 50 to 80% yield and characterised through several spectrographic techniques. Antioxidant activity was assayed using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS). The products exhibited moderate antioxidant activity, with ethyl 2-(4-((4-formyl-2-methoxyphenoxy)methyl)-1H-1,2,3-triazol-1-yl) acetate showing the highest antioxidant capacity (EC50 = 75.5 µg/mL) among the generated 1,4-disubstituted 1,2,3-triazoles. In conclusion, the generation of these compounds opens new possibilities for the development of new antioxidant agents.

Effect of neuropsychiatric medications on mitochondrial function: For better or for worse

Individuals with mitochondrial disease often present with psychopathological comorbidity, and mitochondrial dysfunction has been proposed as the underlying pathobiology in various psychiatric disorders. Several studies have suggested that medications used to treat neuropsychiatric disorders could directly influence mitochondrial function. This review provides a comprehensive overview of the effect of these medications on mitochondrial function. We collected preclinical information on six major groups of antidepressants and other neuropsychiatric medications and found that the majority of these medications either positively influenced mitochondrial function or showed mixed effects. Only amitriptyline, escitalopram, and haloperidol were identified as having exclusively adverse effects on mitochondrial function. In the absence of formal clinical trials, and until such trials are completed, the data from preclinical studies reported and discussed here could inform medication prescribing practices for individuals with psychopathology and impaired mitochondrial function in the underlying pathology.

Roles of Cannabidiol in the treatment and prevention of Alzheimer's disease by multi-target actions

Alzheimer's disease (AD) is one of the most common neurodegenerative diseases with chronic, progressive, and irreversible characteristics, affecting nearly 50 million older adults worldwide. The pathogenesis of AD includes the formation of senile plaques, the abnormal aggregation of tau protein and the gradual degeneration and death of cerebral cortical cells. The main symptoms are memory loss, cognitive decline and behavioral disorders. Studies indicate that cannabidiol(CBD) possesses various pharmacological activities including anti-inflammatory, anti-oxidation and neuroprotective activities. It has been suggested as a potential multi-target medicine for treatment of AD. In this review, we aim to summarize the underlying mechanisms and protective effects of CBD on signaling pathways and central receptors involved in the pathogenesis of AD, including the endocannabinoid system（eCBs）, the Transient receptor potential vanilloid type 1(TRPV1) receptor, and the Peroxisome proliferator-activated receptor (PPAR) receptor.

Repellent Effects of Selected Organic Leaf Extracts of Tithonia diversifolia (Hemsl.) A. Gray and Vernonia lasiopus (O. Hoffman) against Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae)

Introduction

Sitophilus zeamais infestation is among the major setbacks to sustainable maize farming and availability. It causes an estimated annual loss of 5-10% and 20-30% of the total maize grains loss in the temperate and tropical zones, respectively. Although synthetic pesticides are quick and effective in managing crop pests, their overuse and misuse is discouraged due to their detrimental effects on human and environment. Natural pesticidal products that are extracted from plants are particularly gaining importance as an alternative to synthetic pesticides. They are available, easily biodegraded and have low toxicity to nontarget organisms. Most botanical pesticides act on insects by repelling them away from the crops in the field or in the stores. Therefore, this study aimed to determine repellency potential of organic leaf extracts of Tithonia diversifolia and Vernonia lasiopus on S. zeamais. Materials and methods. The phytochemical profile of T. diversifolia and V. lasiopus was determined using GC-MS. Laboratory-based experiments were carried out using area preference method to assess the efficacy of the extracts against weevils for a test period of 5 h. Six groups of experiments were set up with ten S. zeamais in each test: positive control (Actellic), negative control (solvent only), and four different experimental extract concentrations (25, 50, 75, and 100%).

Results

The results indicated that T. diversifolia and V. lasiopus leaf extracts possess potent repellency effect on weevils. All the extracts simply discouraged S. zeamais from the treated areas recording significantly good levels of repellent activities between 26 and 96%. Furthermore, the GC-MS analysis manifested the presence of bioactive compound in the extracts which are associated with the repellency effects.

Conclusion

The study scientifically confirms the traditional use of the T. diversifolia and V. lasiopus and provides important platform for further study on the extracts as bioresource of botanical repellent.

Vanillin: a review on the therapeutic prospects of a popular flavouring molecule

Abstract

Graphic abstract

Bilberry (Vaccinium myrtillus L.) Extracts Comparative Analysis Regarding Their Phytonutrient Profiles, Antioxidant Capacity along with the In Vivo Rescue Effects Tested on a Drosophila melanogaster High-Sugar Diet Model

Bilberries (Vaccinium myrtillus L.) have been reported to hold a plentitude of health-promoting properties beyond basic nutrition, mainly attributed to their anthocyanin content and antioxidant activity. In this article, we built the phytochemical profile of three wild bilberry fruit extract formulations (aqueous, methanolic, and hydro-methanolic) using UHPLC-ESI-MS/MS putative analysis, identifying 88 individual phytochemicals, mainly flavonoids (total content 8.41 ± 0.11 mg QE/g dw), free amino acids, polyphenols (total content 21.68 ± 0.19 mg GAE/g dw), carboxylic acids, and vitamins. Furthermore, the antioxidant activity of the extract was assessed, reaching 78.03 ± 0.16% DPPH free radical scavenging activity, comparable to literature values determined for bilberry extracts of other origin. Due to the increased prevalence of metabolic syndrome and based on the reviewed benefits of bilberries, we tested the most potent formulation of our bilberry extracts in this biological context. The in vivo rescue effect of a bilberry extract supplemented diet on Drosophila melanogaster was assessed by monitoring biochemical and genomic markers. Hemolymph trehalose levels were halved upon addition of 3% hydro-methanolic bilberry extract to a high-sugar (1.5 M sucrose) diet, as compared to the non-supplemented high-sugar diet. Noteworthy, the rescue seen for flies kept on the bilberry extract supplemented high-sugar diet appeared to parallel the trehalose levels observed in the case of the control diet (50 mM sucrose) flies. Moreover, next to the trehalose-lowering type of in vivo effects, other gene expression related rescues were also detected for genes such as InR, Akh, AstA, AstC, Irk, Npc2g, and CCHa2 upon supplementation of the high-sugar diet with our hydro-methanolic bilberry fruit extract. Our findings suggest that such a bilberry fruit extract could generate physiological and genomic type of compensatory mechanisms so that further translational approaches would advance the understanding of some human specific pathological conditions.

The beneficial effect of vanillin on 6-hydroxydopamine rat model of Parkinson's disease

BACKGROUND

Parkinson's disease (PD) is a progressive neurodegenerative disorder that is related to neuroinflammation. Vanillin, which possesses both antioxidant, and anti-inflammatory properties, can be a candidate for neuroprotection in PD.

OBJECTIVE

This study was aimed to investigate the effects of vanillin on the 6-hydroxydopamine (6-OHDA) rodent model of PD.

METHODS

Male Wistar rats were administrated intraperitoneal (i.p) or oral vanillin at a dose of 20 mg/kg/day for 7 days that was started at three days before or seven days after intracerebral injection of 6-OHDA. The 6-OHDA-induced lesions were assessed behaviorally using the apomorphine rotation test, neurochemically via measuring striatal dopamine concentrations, and through immunohistochemistry.

RESULTS

Both oral and IP vanillin at three days before or seven days after 6-OHDA lesioning exhbited significantly lower tight contralateral rotations upon apomorphine challenge, and higher striatal dopamine concentrations.

CONCLUSIONS

Vanillin seems to offer protective properties against 6-OHDA lesion via preserving striatal dopamine levels.

Possible involvement of D2/D3 receptor activation in ischemic preconditioning mediated protection of the brain

Ischemic stroke is a medical condition that arises because of poor blood supply to the brain. Reperfusion being salvage to the brain further causes, exacerbation of tissue injury, known as reperfusion injury. Ischemic preconditioning (IPC) has been known to provide benefits against ischemia reperfusion (I/R) injury. Dopamine D2/D3 receptor mediated several pathways are also reported as mediators in the IPC mediated neuroprotection. This study investigates the possible involvement of D2/D3 receptor activation in IPC mediated neuroprotection in the I/R brain. Global cerebral ischemia/reperfusion (GCI/R) injury in swiss albino mice was induced by occluding the common carotid arteries for 17 min, followed by 24 h reperfusion. IPC was provided by giving 3 episodes of I/R prior to Ischemia (17 min). Morris water maze (MWM) was used to assess the spatial learning, memory and Rota rod, lateral push test as well as inclined beam test were conducted to assess the motor functions in animals. Cerebral oxidative markers (thiobarbituric acid reactive species-TBARS, reduced glutathione-GSH, superoxide dismutase-SOD, and catalase-CAT), inflammatory markers (IL-6, IL-10, TNF-α, and myeloperoxidase-MPO), acetylcholinesterase activity-AChE, infarct size (% weight and % volume), and histopathological changes were also assessed. Haloperidol (0.05 mg/kg, i.p) was used to antagonize the effects of D2/D3 receptor activation. I/R animals showed reduction in memory, motor function, increase in cerebral oxidative stress, inflammation, AChE activity, infarct size and histopathological changes. Episodes of IPC prior to ischemia, attenuated the deleterious effects of I/R injury. Administration of haloperidol abolished the protective effects of IPC. Hence, it may be concluded that IPC mediated neuroprotection may involves dopamine D2/D3 receptor activation in mice.

Vanillin protects lipopolysaccharide-induced acute lung injury by inhibiting ERK1/2, p38 and NF-κB pathway

Aim: Thus far, the anti-inflammatory effect of vanillin in acute lung injury (ALI) has not been studied. This study aimed to investigate the effect of vanillin in lipopolysaccharide (LPS)-induced ALI. Results & methodology: Our study detected the anti-inflammatory effects of vanillin by ELISA and western blot, respectively. Pretreatment of mice with vanillin significantly attenuated LPS-stimulated lung histopathological changes, myeloperoxidase activity and expression levels of proinflammatory cytokines by inhibiting the phosphorylation activities of ERK1/2, p38, AKT and NF-κB p65. In addition, vanillin inhibited LPS-induced TNF-α and IL-6 expression in RAW264.7 cells via ERK1/2, p38 and NF-κB signaling. Conclusion: Vanillin can inhibit macrophage activation and lung inflammation, which suggests new insights for clinical treatment of ALI.

The Changes of Expression and Methylation of Genes Involved in Oxidative Stress in Course of Chronic Mild Stress and Antidepressant Therapy with Agomelatine

Preclinical studies conducted so far suggest that oxidative stress processes may be associated with the mechanism of depression development. This study shows the effects of chronic administration of agomelatine on expression and the methylation status of Sod1, Sod2, Gpx1, Gpx4, Cat, Nos1, and Nos2 in the brain stricture and blood in the chronic mild stress (CMS) animal model of depression. The animals were exposed to the CMS procedure and treatment with agomelatine (10 mg/kg/day, IP) for five weeks and then were sacrificed. TaqMan Gene Expression Assay, Western blot, and methylation-sensitive high-resolution melting techniques were used to evaluate mRNA and protein expression of the genes, and the methylation status of their promoters. Gpx1, Gpx4, and Sod2 expression in the PBMCs and Sod1 and Sod2 expression in the brain were reduced in the stressed group after agomelatine administration. CMS caused an increase in the methylation of the third Gpx4 promoter in peripheral blood mononuclear cells and Gpx1 promoter in the cerebral cortex. Additionally, stressed rats treated with agomelatine displayed a significantly lower Gpx4 level in the hypothalamus. The results confirm the hypothesis that the CMS procedure and agomelatine administration change the expression level and methylation status of the promoter region of genes involved in oxidative and nitrosative stress.

The Novel Potential Therapeutic Utility of Montelukast in Alleviating Autistic Behavior Induced by Early Postnatal Administration of Thimerosal in Mice

BACKGROUND AND AIM: Thimerosal (THIM) is a mercury-containing preservative widely used in many biological and medical products including many vaccines. It has been accused of being a possible etiological factor for some neurodevelopmental disorders such as autistic spectrum disorders (ASDs). In our study, the potential therapeutic effect of montelukast, a leukotriene receptor antagonist used to treat seasonal allergies and asthma, on THIM mice model (ASDs model) was examined.

METHODOLOGY

Newborn mice were randomly distributed into three groups: (Group 1) Control (Cont.) group received saline injections. (Group 2) THIM-treated (THIM) group received THIM intramuscular (IM) at a dose of 3000 μg Hg/kg on postnatal days 7, 9, 11, and 15. (Group 3) Montelukast-treated (Monte) group received THIM followed by montelukast sodium (10 mg/kg/day) intraperitoneal (IP) for 3 weeks. Mice were evaluated for growth development, social interactions, anxiety, locomotor activity, and cognitive function. Brain histopathology, alpha 7 nicotinic acetylcholine receptors (α7nAChRs), nuclear factor kappa B p65 (NF-κB p65), apoptotic factor (Bax), and brain injury markers were evaluated as well.

RESULTS

THIIM significantly impaired social activity and growth development. Montelukast mitigated THIM-induced social deficit probably through α7nAChRs upregulation, NF-κB p65, Bax, and brain injury markers downregulation, thus suppressing THIM-induced neuronal toxicity and inflammation.

CONCLUSION

Neonatal exposure to THIM can induce growth retardation and abnormal social interactions similar to those observed in ASDs. Some of these abnormalities could be ameliorated by montelukast via upregulation of α7nAChRs that inhibited NF-κB activation and significant suppression of neuronal injury and the associated apoptosis.

Psychotropic and neurological medication effects on mitochondrial complex I and IV in rodent models

Mitochondrial complex I (NADH-dehydrogenase) and complex IV (cytochrome-c-oxidase) are reported to be affected by drugs used to treat psychiatric or neurodegenerative diseases, including antidepressants, antipsychotics, anxiolytics, mood stabilizers, stimulants, antidementia, and antiparkinsonian drugs. We conducted meta-analyses examining the effects of each drug category on complex I and IV. The electronic databases Pubmed, EMBASE, CENTRAL, and Google Scholar were searched for studies published between 1970 and 2018. Of 3105 screened studies, 68 articles covering 53 drugs were included in the meta-analyses. All studies assessed complex I and IV in rodent brain at the level of enzyme activity. Results revealed that selected antidepressants increase or decrease complex I and IV, antipsychotics and stimulants decrease complex I but increase complex IV, whereas anxiolytics, mood stabilizers, antidementia, and antiparkinsonian drugs preserve or even enhance both complex I and IV. Potential contributions to the drug effects were found to be related to the drugs' neurotransmitter receptor profiles with adrenergic (α1B), dopaminergic (D1/2), glutaminergic (NMDA1,3), histaminergic (H1), muscarinic (M1,3), opioid (OP1-3), serotonergic (5-HT_2A, 5-HT_2C, 5-HT_3A) and sigma (σ1) receptors having the greatest effects. The findings are discussed in relation to pharmacological mechanisms of action that might have relevance for clinical and research applications.

Beneficial role of vanillin, a polyphenolic flavoring agent, on maneb-induced oxidative stress, DNA damage, and liver histological changes in Swiss albino mice

Vanillin, a widely used flavoring agent, has antimutagenic and antioxidant properties. The current study was performed to evaluate its beneficial role against hepatotoxicity induced by maneb, a dithiocarbamate fungicide. Mice were divided into four groups of six each: group 1, serving as negative controls which received by intraperitoneal way only distilled water, a solvent of maneb; group 2, received daily, by intraperitoneal way, maneb (30 mg kg^-1 body weight (BW)); group 3, received maneb at the same dose of group 2 and 50 mg kg^-1 BW of vanillin by intraperitoneal way; and group 4, serving as positive controls, received daily only vanillin. After 10 days of treatment, mice of all groups were killed. Our results showed that vanillin significantly reduced the elevated hepatic levels of malondialdehyde, hydrogen peroxide, and advanced oxidation protein product and attenuated DNA fragmentation induced by maneb. In addition, vanillin modulated the alterations of antioxidant status: enzymatic (superoxide dismutase, catalase, and glutathione peroxidase) and nonenzymatic (reduced glutathione, nonprotein thiol, and vitamin C) antioxidants in the liver of maneb-treated mice. This natural compound was also able to ameliorate plasma biochemical parameters (aspartate aminotransferase, alanine aminotransferase, gamma glutamyl transpeptidase, alkaline phosphatase, total bilirubin, and total protein). The protective effect of vanillin was further evident through the histopathological changes produced by maneb in the liver tissue. Thus, we concluded that vanillin might be beneficial against maneb-induced hepatic damage in mice.

Oleoylethanolamide, Neuroinflammation, and Alcohol Abuse

Neuroinflammation is a complex process involved in the physiopathology of many central nervous system diseases, including addiction. Alcohol abuse is characterized by induction of peripheral inflammation and neuroinflammation, which hallmark is the activation of innate immunity toll-like receptors 4 (TLR4). In the last years, lipid transmitters have generated attention as modulators of parts of the addictive process. Specifically, the bioactive lipid oleoylethanolamide (OEA), which is an endogenous acylethanolamide, has shown a beneficial profile for alcohol abuse. Preclinical studies have shown that OEA is a potent anti-inflammatory and antioxidant compound that exerts neuroprotective effects in alcohol abuse. Exogenous administration of OEA blocks the alcohol-induced TLR4-mediated pro-inflammatory cascade, reducing the release of proinflammatory cytokines and chemokines, oxidative and nitrosative stress, and ultimately, preventing the neural damage in frontal cortex of rodents. The mechanisms of action of OEA are discussed in this review, including a protective action in the intestinal barrier. Additionally, OEA blocks cue-induced reinstatement of alcohol-seeking behavior and reduces the severity of withdrawal symptoms in animals, together with the modulation of alcohol-induced depression-like behavior and other negative motivational states associated with the abstinence, such as the anhedonia. Finally, exposure to alcohol induces OEA release in blood and brain of rodents. Clinical evidences will be highlighted, including the OEA release and the correlation of plasma OEA levels with TLR4-dependent peripheral inflammatory markers in alcohol abusers. In base of these evidences we hypothesize that the endogenous release of OEA could be a homeostatic signal to counteract the toxic action of alcohol and we propose the exploration of OEA-based pharmacotherapies to treat alcohol-use disorders.

Activation of TRPV1 receptors affects memory function and hippocampal TRPV1 and CREB mRNA expression in a rat model of biliary cirrhosis

OBJECTIVE

Memory impairment induced by biliary cirrhosis is associated with abnormalities in the function of different neurotransmitter systems. However, the exact molecular mechanisms involved in the learning and memory dysfunctions following biliary cirrhosis is largely unknown. This study set out to determine whether activation of transient receptor potential vanilloid type 1 (TRPV1) in the CA1 area of the hippocampus in rats improve memory impairment induced by biliary cirrhosis.

METHODS

To assess learning and memory, passive avoidance task was carried out using a shuttle box. The mRNA expression of TRPV1 and cAMP response element binding (CREB) protein in the hippocampus were also evaluated by qT-PCR.

RESULTS

Our results indicated that activation of TRPV1 channels by capsaicin significantly decreased memory impairment and increased mRNA expression of the TRPV1 and CREB in the hippocampus of rats with biliary cirrhosis. Our findings also demonstrated that a positive correlation existed between mRNA expression of TRPV1 and CREB, and between memory function and TRPV1 expression.

DISCUSSION

Taken together, the results of this study support the view that TRPV1 receptor may play an important role in the regulation of learning and memory functions, and suggest that activation of TRPV1 channels seems to be a promising therapeutic target for learning and memory impairments following biliary cirrhosis.

Modulation of the Oxidative Stress and Lipid Peroxidation by Endocannabinoids and Their Lipid Analogues

Growing evidence supports the pivotal role played by oxidative stress in tissue injury development, thus resulting in several pathologies including cardiovascular, renal, neuropsychiatric, and neurodegenerative disorders, all characterized by an altered oxidative status. Reactive oxygen and nitrogen species and lipid peroxidation-derived reactive aldehydes including acrolein, malondialdehyde, and 4-hydroxy-2-nonenal, among others, are the main responsible for cellular and tissue damages occurring in redox-dependent processes. In this scenario, a link between the endocannabinoid system (ECS) and redox homeostasis impairment appears to be crucial. Anandamide and 2-arachidonoylglycerol, the best characterized endocannabinoids, are able to modulate the activity of several antioxidant enzymes through targeting the cannabinoid receptors type 1 and 2 as well as additional receptors such as the transient receptor potential vanilloid 1, the peroxisome proliferator-activated receptor alpha, and the orphan G protein-coupled receptors 18 and 55. Moreover, the endocannabinoids lipid analogues N-acylethanolamines showed to protect cell damage and death from reactive aldehydes-induced oxidative stress by restoring the intracellular oxidants-antioxidants balance. In this review, we will provide a better understanding of the main mechanisms triggered by the cross-talk between the oxidative stress and the ECS, focusing also on the enzymatic and non-enzymatic antioxidants as scavengers of reactive aldehydes and their toxic bioactive adducts.

Capsaicin Attenuates Amyloid-β-Induced Synapse Loss and Cognitive Impairments in Mice

Alzheimer's disease (AD) is the most common cause of progressive cognitive impairment in the aged. The aggregation of the amyloid β-protein (Aβ) is a hallmark of AD and is linked to synapse loss and cognitive impairment. Capsaicin, a specific agonist of the transient receptor potential vanilloid 1 (TRPV1), has been proven to ameliorate stress-induced AD-like pathological and cognitive impairments, but it is unclear whether TRPV1 activation can affect cognitive and synaptic functions in Aβ-induced mouse model of AD. In this study, we investigated the effects of TRPV1 activation on spatial memory and synaptic plasticity in mice treated with Aβ. To induce AD-like pathological and cognitive impairments, adult C57Bl/6 mice were microinjected with Aβ42 (100 μM, 2.5 μl/mouse, i.c.v.). Two weeks after Aβ42 microinjection, spatial learning and memory as well as hippocampal long-term potentiation (LTP) were examined. The results showed that Aβ42 microinjection significantly impaired spatial learning and memory in the Morris water maze and novel object recognition tests compared with controls. These behavioral changes were accompanied by synapse loss and impaired LTP in the CA1 area of hippocampus. More importantly, daily capsaicin (1 mg/kg, i.p.) treatment throughout the experiment dramatically improved spatial learning and memory and synaptic function, as reflected by enhanced hippocampal LTP and reduced synapse loss, whereas the TRPV1 antagonist capsazepine (1 mg/kg, i.p.) treatment had no effects on cognitive and synaptic function in Aβ42-treated mice. These results indicate that TRPV1 activation by capsaicin rescues cognitive deficit in the Aβ42-induced mouse model of AD both structurely and functionally.

Vanillin improves scopolamine‑induced memory impairment through restoration of ID1 expression in the mouse hippocampus

4-Hydroxy-3-methoxybenzaldehyde (vanillin), contained in a number of species of plant, has been reported to display beneficial effects against brain injuries. In the present study, the impact of vanillin on scopolamine‑induced alterations in cognition and the expression of DNA binding protein inhibitor ID‑1 (ID1), one of the inhibitors of DNA binding/differentiation proteins that regulate gene transcription, in the mouse hippocampus. Mice were treated with 1 mg/kg scopolamine with or without 40 mg/kg vanillin once daily for 4 weeks. Scopolamine‑induced cognitive impairment was observed from 1 week and was deemed to be severe 4 weeks following the administration of scopolamine. However, treatment with vanillin in scopolamine‑treated mice markedly attenuated cognitive impairment 4 weeks following treatment with scopolamine. ID1‑immunoreactive cells were revealed in the hippocampus of vehicle‑treated mice, and were hardly detected 4 weeks following treatment with scopolamine. However, treatment with vanillin in scopolamine‑treated mice markedly restored ID1‑immunoreactive cells and expression 4 weeks subsequent to treatment. The results of the present study suggested that vanillin may be beneficial for cognitive impairment, by preventing the reduction of ID1 expression which may be associated with cognitive impairment.

Novel vanillin derivatives: Synthesis, anti-oxidant, DNA and cellular protection properties

Antioxidants have been the subject of intense research interest mainly due to their beneficial properties associated with human health and wellbeing. Phenolic molecules, such as naturally occurring Resveratrol and Vanillin, are well known for their anti-oxidant properties, providing a starting point for the development of new antioxidants. Here we report, for the first time, the synthesis of a number of new vanillin through the reductive amination reaction between vanillin and a selection of amines. All the compounds synthesised, exhibited strong antioxidant properties in DPPH, FRAP and ORAC assays, with compounds 1b and 2c being the most active. The latter also demonstrated the ability to protect plasmid DNA from oxidative damage in the presence of the radical initiator AAPH. At cellular level, neuroblastoma SH-SY5Y cells were protected from oxidative damage (H₂O₂, 400 μM) with both 1b and 2c. The presence of a tertiary amino group, along with the number of vanillin moieties in the molecule contribute for the antioxidant activity. Furthermore, the delocalization of the electron pair of the nitrogen and the presence of an electron donating substituent to enhance the antioxidant properties of this new class of compounds. In our opinion, vanillin derivatives 1b and 2c described in this work can provide a viable platform for the development of antioxidant based therapeutics.

Modulation of neuroinflammation: Role and therapeutic potential of TRPV1 in the neuro-immune axis

Transient receptor potential vanilloid type 1 channel (TRPV1), as a ligand-gated non-selective cation channel, has recently been demonstrated to have wide expression in the neuro-immune axis, where its multiple functions occur through regulation of both neuronal and non-neuronal activities. Growing evidence has suggested that TRPV1 is functionally expressed in glial cells, especially in the microglia and astrocytes. Glial cells perform immunological functions in response to pathophysiological challenges through pro-inflammatory or anti-inflammatory cytokines and chemokines in which TRPV1 is involved. Sustaining inflammation might mediate a positive feedback loop of neuroinflammation and exacerbate neurological disorders. Accumulating evidence has suggested that TRPV1 is closely related to immune responses and might be recognized as a molecular switch in the neuroinflammation of a majority of seizures and neurodegenerative diseases. In this review, we evidenced that inflammation modulates the expression and activity of TRPV1 in the central nervous system (CNS) and TRPV1 exerts reciprocal actions over neuroinflammatory processes. Together, the literature supports the hypothesis that TRPV1 may represent potential therapeutic targets in the neuro-immune axis.

Vanillin and 4-hydroxybenzyl alcohol attenuate cognitive impairment and the reduction of cell proliferation and neuroblast differentiation in the dentate gyrus in a mouse model of scopolamine-induced amnesia

4-Hydroxy-3-methoxybenzaldehyde (vanillin) and 4-hydroxybenzyl alcohol (4-HBA) are natural phenolic compounds, which present in many plants and have diverse biological properties. In this study, we examined effects of vanillin and 4-HBA on learning and memory function, cell proliferation, and neuroblast differentiation in the hippocampal dentate gyrus in a mouse model of scopolamine-induced amnesia. Scopolamine (SCO; 1 mg/kg/day, intraperitoneally), vanillin, and 4-HBA (40 mg/kg/day, orally) were administered for 28 days. Treatment with scopolamine alone impaired learning and memory function in the Morris water maze and passive avoidance tests, in addition, the treatment significantly reduced cell proliferation and neuroblast differentiation in the dentate gyrus, which were examined by immunohistochemistry for Ki-67 (a classic marker for cell proliferation) and doublecortin (a marker for neuroblasts). However, treatment with vanillin or 4-HBA significantly attenuated SCO-induced learning and memory impairment as well as the reduction of cell proliferation and neuroblast differentiation in the dentate gyrus. These results indicate that vanillin and 4-HBA may be helpful in improving cognitive function and in increasing endogenous neuronal proliferation in the brain.

Vanillin Protects Dopaminergic Neurons against Inflammation-Mediated Cell Death by Inhibiting ERK1/2, P38 and the NF-κB Signaling Pathway

Neuroinflammation plays a very important role in the pathogenesis of Parkinson’s disease (PD). After activation, microglia produce pro-inflammatory mediators that damage surrounding neurons. Consequently, the inhibition of microglial activation might represent a new therapeutic approach of PD. Vanillin has been shown to protect dopaminergic neurons, but the mechanism is still unclear. Herein, we further study the underlying mechanisms in lipopolysaccharide (LPS)-induced PD models. In vivo, we firstly established rat models of PD by unilateral injection of LPS into substantia nigra (SN), and then examined the role of vanillin in motor dysfunction, microglial activation and degeneration of dopaminergic neurons. In vitro, murine microglial BV-2 cells were treated with vanillin prior to the incubation of LPS, and then the inflammatory responses and the related signaling pathways were analyzed. The in vivo results showed that vanillin markedly improved the motor dysfunction, suppressed degeneration of dopaminergic neurons and inhibited microglial over-activation induced by LPS intranigral injection. The in vitro studies demonstrated that vanillin reduces LPS-induced expression of inducible nitric oxide (iNOS), cyclooxygenase-2 (COX-2), IL-1β, and IL-6 through regulating ERK1/2, p38 and NF-κB signaling. Collectively, these data indicated that vanillin has a role in protecting dopaminergic neurons via inhibiting inflammatory activation.

Agomelatine reduces brain, kidney and liver oxidative stress but increases plasma cytokine production in the rats with chronic mild stress-induced depression

Agomelatine (AGOM) as an antidepressant acts both as a melatonin-receptor agonist and a selective serotonin-receptor antagonist. As a potent melatonin derived antioxidant, AGOM might modulate depression-induced lipid peroxidation and pro-inflammatory cytokines in brain, kidney and liver. The present study explores whether AGOM protects against experimental depression-induced brain, kidney and liver oxidative stress, and plasma cytokine production in rats with chronic mild stress (CMS)-induced depression. Thirty-six rats were divided into four groups. The first group was used as an untreated control. The second group received AGOM for 4 weeks. The third group was exposed to chronic mild stress (CMS) of 4 weeks for induction depression. The fourth group received 40 mg/kg AGOM and CMS for 4 weeks. Liver and kidney lipid peroxidation levels were high in the CMS group although they were low in AGOM treatments. AGOM and AGOM + CMS treatments increased the lowered glutathione peroxidase activity and reduced glutathione levels in brain, kidney and liver of CMS group. β-carotene, vitamin A and vitamin E concentrations in the brain, kidney and liver of the four groups were not changed by CMS and AGOM treatments. However, plasma TNF-α, interleukin (IL)-1β, and IL-4 levels were high in the CMS and AGOM group and their levels were further increased by the AGOM + CMS treatment. In conclusions, AGOM induced protective effects against experimental depression-induced brain, kidney, and liver oxidative injuries through regulation of the glutathione concentrations and glutathione peroxidase activity. However, plasma cytokine productions were increased by the AGOM treatment.

Neuroprotective Effects of Nicorandil in Chronic Cerebral Hypoperfusion-Induced Vascular Dementia

BACKGROUND

Ischemia-induced chronic cerebral hypoperfusion (CCH) is associated with reduced cerebral blood flow and vascular dementia (VaD). Brain mitochondrial potassium (adenosine triphosphate-sensitive potassium [K_ATP]) channels have a beneficial role in various brain conditions. The utility of K_ATP channels in CCH-induced VaD is still unknown. The aim of this study is to investigate the role of nicorandil, a selective K_ATP channel opener, in CCH-induced VaD.

METHODS

The method of 2-vessel occlusion (2VO) was used to induce CCH in mice. Cognitive impairment was assessed using Morris water maze. Serum nitrosative stress (nitrite/nitrate), brain cholinergic dysfunction (acetylcholinesterase [AChE] activity), brain oxidative stress (thiobarbituric acid reactive substances, glutathione [GSH], catalase [CAT], and superoxide dismutase [SOD]), inflammation (myeloperoxidase [MPO]), and infarct size (2,3,5-triphenyltetrazolium chloride staining) were assessed.

RESULTS

2-vessels-occluded animals have shown significant cognitive impairment, serum nitrosative stress (reduced nitrite/nitrate), cholinergic dysfunction (increased brain AChE activity), and increased brain oxidative stress (reduction in GSH content and SOD and CAT activities with a significant increase in lipid peroxidation), along with a significant increase in MPO activity and infarct size. However, nicorandil treatment has significantly attenuated various CCH-induced behavioral and biochemical impairments.

CONCLUSIONS

It may be said that 2VO provoked CCH leading to VaD, which was attenuated by the treatment of nicorandil. So, modulation of K_ATP channels may provide benefits in CCH-induced VaD.

Linking mitochondrial dysfunction, metabolic syndrome and stress signaling in Neurodegeneration

Mounting evidence suggests a link between metabolic syndrome (MetS) such as diabetes, obesity, non-alcoholic fatty liver disease in the progression of Alzheimer's disease (AD), Parkinson's disease (PD) and other neurodegenerative diseases (NDDs). For instance, accumulated Aβ oligomer is enhancing neuronal Ca²⁺ release and neural NO where increased NO level in the brain through post translational modification is modulating the level of insulin production. It has been further confirmed that irrespective of origin; brain insulin resistance triggers a cascade of the neurodegeneration phenomenon which can be aggravated by free reactive oxygen species burden, ER stress, metabolic dysfunction, neuorinflammation, reduced cell survival and altered lipid metabolism. Moreover, several studies confirmed that MetS and diabetic sharing common mechanisms in the progression of AD and NDDs where mitochondrial dynamics playing a critical role. Any mutation in mitochondrial DNA, exposure of environmental toxin, high-calorie intake, homeostasis imbalance, glucolipotoxicity is causative factors for mitochondrial dysfunction. These cumulative pleiotropic burdens in mitochondria leads to insulin resistance, increased ROS production; enhanced stress-related enzymes that is directly linked MetS and diabetes in neurodegeneration. Since, the linkup mechanism between mitochondrial dysfunction and disease phenomenon of both MetS and NDDs is quite intriguing, therefore, it is pertinent for the researchers to identify and implement the therapeutic interventions for targeting MetS and NDDs. Herein, we elucidated the pertinent role of MetS induced mitochondrial dysfunction in neurons and their consequences in NDDs. Further, therapeutic potential of well-known biomolecules and chaperones to target altered mitochondria has been comprehensively documented. This article is part of a Special Issue entitled: Oxidative Stress and Mitochondrial Quality in Diabetes/Obesity and Critical Illness Spectrum of Diseases - edited by P. Hemachandra Reddy.

Protective effect of transient receptor potential vanilloid subtype 1 (TRPV1) modulator, against behavioral, biochemical and structural damage in experimental models of Alzheimer's disease

Alzheime's disease (AD) is an overwhelming neurodegenerative disorder, characterized by synaptic dysfunction, memory loss, neuro-inflammation and neural cell death. Very few treatments are in hand for the management of AD and they are only concentrating on peculiar aspects. Hence, an immense thrust is required to find utmost therapeutic targets to conquer this condition. This study investigates a potential role of vanillin, a selective agonist of transient receptor potential vanilloid subtype 1 (TRPV1) in the experimental models of AD viz. intracerebroventricular (i.c.v.) streptozotocin (STZ) and aluminum trichloride (AlCl3)+d-galactose induced AD in mice. The i.c.v. administration of STZ and intraperitoneally administration of AlCl3+d-galactose have significantly impaired learning-memory (Morris water maze and attentional set-shifting test), brain structure (hematoxylin, eosin and Congo red staining), enhanced brain oxidative stress (thiobarbituric acid reactive substance - TBARS and glutathione - GSH), nitrosative stress (nitrite/nitrate), acetylcholinesterase activity (AChE), inflammation (MPO), and calcium levels (Ca(++)). Treatment with vanillin in different doses and donepezil have significantly ameliorated i.c.v. STZ and AlCl3+d-galactose induced reduction in executive function, impaired reversal learning, cognition, memory and brain damage. Treatment with these drugs has also reduced the brain oxidative stress (TBARS and GSH), nitrosative stress (nitrite/nitrate), and AChE, MPO, and Ca(++) levels. These results indicate that vanillin, a selective agonist of TRPV1 and donepezil, a potent acetylcholine esterase inhibitor have attenuated i.c.v. STZ and AlCl3+d-galactose induced experimental AD. Hence, pharmacological positive modulation of TRPV1 channels may be a potential research target for mitigation of AD.

Vanillin Attenuated Behavioural Impairments, Neurochemical Deficts, Oxidative Stress and Apoptosis Against Rotenone Induced Rat Model of Parkinson's Disease

Vanillin (4-hydroxy-3-methoxybenzaldehyde), a pleasant smelling organic aromatic compound, is widely used as a flavoring additive in food, beverage, cosmetic and drug industries. It is reported to cross the blood brain barrier and also displayed antioxidant and neuroprotective activities. We previously reported the neuroprotective effect of vanillin against rotenone induced in in vitro model of PD. The present experiment was aimed to analyze the neuroprotective effect of vanillin on the motor and non-motor deficits, neurochemical variables, oxidative, anti-oxidative indices and the expression of apoptotic markers against rotenone induced rat model of Parkinson's disease (PD). Rotenone treatment exhibited motor and non-motor impairments, neurochemical deficits, oxidative stress and apoptosis, whereas oral administration of vanillin attenuated the above-said indices. However further studies are needed to explore the mitochondrial protective and anti-inflammatory properties of vanillin, as these processes play a vital role in the cause and progression of PD.

The Protective Role of Selenium on Scopolamine-Induced Memory Impairment, Oxidative Stress, and Apoptosis in Aged Rats: The Involvement of TRPM2 and TRPV1 Channels

Inhibition of Ca²⁺ entry into the hippocampus and dorsal root ganglion (DRG) through inhibition of N-methyl-D-aspartate (NMDA) receptor antagonist drugs is the current standard of care in neuronal diseases such as Alzheimer's disease, dementia, and peripheral pain. Oxidative stress activates Ca²⁺-permeable TRPM2 and TRPV1, and recent studies indicate that selenium (Se) is a potent TRPM2 and TRPV1 channel antagonist in the hippocampus and DRG. In this study, we investigated the neuroprotective properties of Se in primary hippocampal and DRG neuron cultures of aged rats when given alone or in combination with scopolamine (SCOP). Thirty-two aged (18-24 months old) rats were divided into four groups. The first and second groups received a placebo and SCOP (1 mg/kg/day), respectively. The third and fourth groups received intraperitoneal Se (1.5 mg/kg/ over day) and SCOP + Se, respectively. The hippocampal and DRG neurons also were stimulated in vitro with a TRPV1 channel agonist (capsaicin) and a TRPM2 channel agonist (cumene hydroperoxide). We found that Se was fully effective in reversing SCOP-induced TRPM2 and TRPV1 current densities as well as errors in working memory and reference memory. In addition, Se completely reduced SCOP-induced oxidative toxicity by modulating lipid peroxidation, reducing glutathione and glutathione peroxidase. The Se and SCOP + Se treatments also decreased poly (ADP-ribose) polymerase activity, intracellular free Ca²⁺ concentrations, apoptosis, and caspase 3, caspase 9, and mitochondrial membrane depolarization values in the hippocampus. In conclusion, the current study reports on the cellular level for SCOP and Se on the different endocytotoxic cascades for the first time. Notably, the research indicates that Se can result in remarkable neuroprotective and memory impairment effects in the hippocampal neurons of rats. Graphical abstract Possible molecular pathways of involvement of selenium (Se) in scopolamine (SCOP) induced apoptosis, oxidative stress, and calcium accumulation through TRPM2 and TRPV1 channels in the hippocampus neurons of aged rats. The TRPM2 channel is activated by ADP-ribose and oxidative stress, although it is inhibited by ACA. The TRPV1 channel is activated by oxidative stress and capsaicin, and it is blocked by capsazepine (CPZ). The beta-amyloid plaque induces oxidative stress in hippocampus. SCOP can result in augmented ROS release in hippocampal neurons, leading to Ca²⁺ uptake through TRPM2 and TRPV1 channels. Mitochondria were reported to accumulate Ca²⁺ provided that intracellular Ca²⁺ rises, thereby leading to the depolarization of mitochondrial membranes and release of apoptosis-inducing factors such as caspase 3 and caspase 9. Se reduced TRPM2 and TRPV1 channel activation through the modulation of aging oxidative reactions and Se-dependent glutathione peroxidase (GSH-Px) antioxidant pathways.

Modulation of Diabetes-Induced Oxidative Stress, Apoptosis, and Ca2+ Entry Through TRPM2 and TRPV1 Channels in Dorsal Root Ganglion and Hippocampus of Diabetic Rats by Melatonin and Selenium

Neuropathic pain and hippocampal injury can arise from the overload of diabetes-induced calcium ion (Ca²⁺) entry and oxidative stress. The transient receptor potential (TRP) melastatin 2 (TRPM2) and TRP vanilloid type 1 (TRPV1) are expressed in sensory neurons and hippocampus. Moreover, activations of TRPM2 and TRPV1 during oxidative stress have been linked to neuronal death. Melatonin (MEL) and selenium (Se) have been considered potent antioxidants that detoxify a variety of reactive oxygen species (ROS) in neurological diseases. In order to better characterize the actions of MEL and Se in diabetes-induced peripheral pain and hippocampal injury through modulation of TRPM2 and TRPV1, we tested the effects of MEL and Se on apoptosis and oxidative stress in the hippocampal and dorsal root ganglion (DRG) neurons of streptozotocin (STZ)-induced diabetic rats. Fifty-eight rats were divided into six groups. The first group was used as control. The second group was used as the diabetic group. The third and fourth groups received Se and MEL, respectively. Intraperitoneal Se and MEL were given to diabetic rats in the fifth and sixth groups. On the 14th day, hippocampal and DRG neuron samples were freshly taken from all animals. The neurons were stimulated with a TRPV1 channel agonist (capsaicin) and a TRPM2 channel agonist (cumene hydroperoxide). We observed a modulator role of MEL and Se on intracellular free Ca²⁺ concentrations, current densities of TRPM2 and TRPV1 channels, apoptosis, caspase 3, caspase 9, mitochondrial depolarization, reduced glutathione, glutathione peroxidase, lipid peroxidation, and intracellular ROS production values in the neurons. In addition, procaspase 3 and 9 activities in western blot analyses of the brain cortex were also decreased by MEL and Se treatments. In conclusion, in our diabetes experimental model, TRPM2 and TRPV1 channels are involved in the Ca²⁺ entry-induced neuronal death and modulation of this channel activity by MEL and Se treatment may account for their neuroprotective activity against apoptosis and Ca²⁺ entry. Graphical Abstract Possible molecular pathways of involvement of melatonin and selenium in diabetes-induced apoptosis, oxidative stress, and calcium accumulation through TRPM2 and TRPV1 channels in the hippocampus and DRG neurons of rats. The TRPM2 channel is activated by ADP-ribose and oxidative stress although it is inhibited by ACA. The TRPV1 channel is activated by oxidative stress and capsaicin and it is blocked by capsazepine (CPZ). Diabetes can result in augmented ROS release in hippocampal and DRG neurons through polyol reactions, leading to Ca²⁺ uptake through TRPM2 and TRPV1 channels. Mitochondria were reported to accumulate Ca²⁺ provided intracellular Ca²⁺ rises, thereby leading to the depolarization of mitochondrial membranes and release of apoptosis-inducing factors such as caspase 3 and caspase 9. Melatonin and selenium reduce TRPM2 and TRPV1 channel activation through the modulation of polyol oxidative reactions and selenium-dependent glutathione peroxidase (GSH-Px) antioxidant pathways.

A novel approach to contrast-induced nephrotoxicity: the melatonergic agent agomelatine

OBJECTIVE

To study the potential nephroprotective role of agomelatine in rat renal tissue in cases of contrast-induced nephrotoxicity (CIN). The drug's action on the antioxidant system and proinflammatory cytokines, superoxide dismutase (SOD) activity, levels of glutathione (GSH) and malondialdehyde (MDA) and the gene expression of interleukin-6 (IL-6), tumour necrosis factor (TNF)-α and nuclear factor kappa B (NF-κB) was measured. Tubular necrosis and hyaline and haemorrhagic casts were also histopathologically evaluated.

METHODS

The institutional ethics and local animal care committees approved the study. Eight groups of six rats were put on the following drug regimens: Group 1: healthy controls, Group 2: GLY (glycerol), Group 3: CM (contrast media--iohexol 10 ml kg(-1)), Group 4: GLY+CM, Group 5: CM+AGO20 (agomelatine 20 mg kg(-1)), Group 6: GLY+CM+AGO20, Group 7: CM+AGO40 (agomelatine 40 mg kg(-1)) and Group 8: GLY+CM+AGO40. The groups were evaluated by one-way analysis of variance and Duncan's multiple comparison test.

RESULTS

Agomelatine administration significantly improved the serum levels of blood urea nitrogen (BUN) and creatinine, SOD activity, GSH and MDA. The use of agomelatine had substantial downregulatory consequences on TNF-α, NF-κB and IL-6 messenger RNA levels. Mild-to-severe hyaline and haemorrhagic casts and tubular necrosis were observed in all groups, except in the healthy group. The histopathological scores were better in the agomelatine treatment groups.

CONCLUSION

Agomelatine has nephroprotective effects against CIN in rats. This effect can be attributed to its properties of reducing oxidative stress and inhibiting the secretion of proinflammatory cytokines (NF-κB, TNF-α and IL-6).

ADVANCES IN KNOWLEDGE

CIN is one of the most important adverse effects of radiological procedures. Renal failure, diabetes, malignancy, old age and non-steroidal anti-inflammatory drug use pose the risk of CIN in patients. Several clinical studies have investigated ways to avoid CIN. Theophylline/aminophylline, statins, ascorbic acid and iloprost have been suggested for this purpose. Agomelatine is one of the melatonin ligands and is used for affective disorders and has antioxidant features. In this study, we hypothesized that agomelatine could have nephroprotective, antioxidant and anti-inflammatory effects against CIN in rats.

Vanillin abrogates ethanol induced gastric injury in rats via modulation of gastric secretion, oxidative stress and inflammation

Vanillin is commonly used as an additive in food, medicine and cosmetics, but its effect has not yet been studied in gastric injury. Therefore the effect of vanillin was studied in experimental gastric ulcer. Gastric secretion and acidity were studied in pylorus ligated rats. Ulcer index, levels of gastric mucus, malondialdehyde (MDA), myeloperoxidase activity (MPO), expression of nuclear factor kappa B (NF-κB) p65, and histopathological changes were determined in ethanol induced gastric ulcer. Pre treatment with vanillin significantly reduced gastric secretion (P < 0.001) and acidity (P < 0.0001) and gastric ulcer index scores (P < 0.001). and augmented the gastric mucosal defense. Vanillin significantly restored the depleted gastric wall mucus levels (P < 0.0001) induced by ethanol and also significantly attenuated ethanol induced inflammation and oxidative stress by the suppression of gastric MPO activity (P < 0.001), reducing the expression of NF-κB p65 and the increased MDA levels (P < 0.001). Vanillin was also effective in alleviating the damage to the histological architecture and the activation of mast cells induced by ethanol.

Together the results of this study highlight the gastroprotective activity of vanillin in gastric ulcers of rats through multiple actions that include inhibition of gastric secretion and acidity, reduction of inflammation and oxidative stress, suppression of expression of NF-κB, and restoration of the histological architecture.