DHA and vitamin E antagonized the Aβ25-35-mediated neuron oxidative damage through activation of Nrf2 signaling pathways and regulation of CD36, SRB1 and FABP5 expression in PC12 cells

Huang X , Zhen J , Dong S , Zhang H , Van Halm-Lutterodt N , Yuan L

Food Funct. 2019 Feb 20;10(2):1049-1061. doi: 10.1039/c8fo01713a.

Abstract

The present study was designed to explore the neuroprotective effects of docosahexaenoic acid (DHA) and/or vitamin E (VE) in vitro. The PC12 cells were pretreated with DHA and/or VE for 4 h, followed by 50 μmol L-1 Aβ25-35 treatments for another 48 h. The cells were then collected and used for the measurements of oxidative stress parameters. Real time-PCR and western blot were applied to measure fatty acid transporters, Nrf2 and its downstream antioxidant targets’ gene and protein expression. Our results indicated that the Aβ25-35 treatment inhibited cellular growth, increased intracellular ROS generation and decreased the mitochondrial membrane potential. The Aβ25-35 treatment decreased the total antioxidant capacity (T-AOC), whereas it increased the MDA levels in neuron cells. Pretreatment of cells with VE or DHA could antagonize the Aβ25-35-mediated cell growth inhibition and mitochondrial membrane potential decline. Activation of the Nrf2 signaling pathway and regulation of CD36, SRB1 and FABP5 expression were observed in DHA- and DHA + VE-pretreated cells. Our results indicated a synergistic effect of DHA and VE in antagonizing the oxidative damage caused by Aβ25-35 in the PC12 cells. The results of the present study will shed light on the application of nutritional intervention for DHA and VE in preventing neuronal damage-related diseases.

Lloret A, Esteve D, Monllor P, Cervera-Ferri A, Lloret A

Int J Mol Sci. 2019 Feb 18;20(4). pii: E879. doi: 10.3390/ijms20040879.

Abstract

Vitamin E was proposed as treatment for Alzheimer’s disease many years ago. However, the effectiveness of the drug is not clear. Vitamin Eis an antioxidant and neuroprotector and it has anti-inflammatory and hypocholesterolemic properties, driving to its importance for brain health. Moreover, the levels of vitamin E in Alzheimer’s disease patients are lower than in non-demented controls. Thus, vitamin E could be a good candidate to have beneficial effects against Alzheimer’s. However, evidence is consistent with a limited effectiveness of vitamin E in slowing progression of dementia; the information is mixed and inconclusive. The question is why does vitamin E fail to treat Alzheimer’s disease? In this paper we review the studies with and without positive results in Alzheimer’s disease and we discuss the reasons why vitamin E as treatment sometimes has positive results on cognition but at others, it does not.

Barzegar-Amini M, Ghazizadeh H, Seyedi SMR, Sadeghnia HR, Mohammadi A, Hassanzade-Daloee M, Barati E, Kharazmi-Khorassani S, Kharazmi-Khorassani J, Mohammadi-Bajgiran M, Tavallaie S, Ferns GA, Mouhebati M, Ebrahimi M, Tayefi M, Ghayour-Mobarhan M

Diabetes Metab Syndr. 2019 Jan - Feb;13(1):666-671. doi: 10.1016/j.dsx.2018.11.034. Epub 2018 Nov 13.

Abstract

OBJECTIVES:

Obesity and overweight are among the main causes of cardiovascular disease (CVD) mortality. Dyslipidemia, fatty liver index, is strongly related to CVD. Vitamin E as an antioxidant protects the hepatic cells against oxidative stress and prevents fatty liver disease. The aim of the current study is to evaluate the relationship between anthropometric parameters and fasted lipid profile with serum vitamin Elevels.

STUDY DESIGN:

A randomized trial was designed based on data from the Mashhad stroke and heart atherosclerotic disorders (MASHAD: 2010-2020).

METHODS:

363 CVD subjects (173 males and 190 females) was selected at random, among 9704 subjects in three regions of Mashhad, northeast of Iran to investigate the specific correlations among their serum vitamin E, lipid profile (TG, HDL-C, LDL-C and TC), and anthropometric features (height, weight, BMI, hip and waist circumferences.

RESULT:

The results indicated the significant relationships between vitamin E, and fasting serum lipid profile in subjects. Serum vitamin Ewas negatively correlated to TC, TG, and LDL-C and positively related to HDL-C. Also, statistically negative correlations were found between vitamin E and anthropometric parameters (weight, waist and hip circumference, middle Arm, and Systolic Blood Pressure). Moreover, vitamin E ratios such as vitamin E/(TC + TG) and vitamin E/TC values as standardized vitamin E, had significant negative correlation with BMI, the whole of anthropometric parameters, and dyslipidemia risk factors including TC, TG and LDL-C.

CONCLUSION:

We found that vitamin E profile was significantly lower in the dyslipidemia subjects. It is generally suggested that vitamin E monitoring might be used as a useful prognostic and therapeutic agent in dyslipidemia disorder.

Yan B, Sun Y, Zeng J, Chen Y, Li C, Song P, Zhang L, Yang X, Wu Y, Ma P

Toxicol Appl Pharmacol. 2019 Feb 15;368:1-17. doi: 10.1016/j.taap.2019.02.008. [Epub ahead of print]

Abstract

Learning disabilities (LDs) in children are a serious global problem. Dibutyl phthalate (DBP), a plasticizer widely used in daily life, has been linked to triggering childhood LDs, however the mechanism underlying this remains unclear. Studies have shown that the ERK 1/2 pathway is closely related to apoptosis of hippocampal neurons. On the basis of these links between LDs, DBP and the ERK 1/2 pathway, we explore whether DBP induces hippocampal neuron apoptosis and increases behavioral disorders in mice via the ERK 1/2 pathway. We looked at oxidative stress, examined the calcium signal, detected the ERK 1/2 pathway and evaluated apoptosis as well as using histological observations, and found that DBP significantly increased oxidative damage and apoptosis in hippocampal neurons via the ERK 1/2 pathway in mice. We also found that pretreatment with the dihydropyridine’s (DHP’s) Ca²⁺ antagonist, nimodipine (NMDP), combined with the antioxidant Vitamin E (VE), attenuated ERK 1/2 phosphorylation and DBP-mediated disorders, suggesting that a combined use of VE and NMDP can ameliorate DBP-induced memory deficit and apoptosis via inhibiting the ERK 1/2 pathway. These results indicate that DBP predisposes oxidative damage and apoptosis in hippocampal neurons by activation of the ERK 1/2 pathway, and may be proposed as a possible mechanism underlying LDs in children. Moreover, VE and NMDP may play a certain protective role in the targeted treatment of childhood LDs.

de Souza CP, Gambeta E, Stern CAJ, Zanoveli JM

Behav Brain Res. 2019 Feb 1;359:749-754. doi: 10.1016/j.bbr.2018.09.008. Epub 2018 Sep 13

Abstract

Anxiety and stress disorders, such as posttraumatic stress disorder (PTSD) have been described as debilitating comorbidities of diabetes. In the present study, we aimed to investigate anxiety-like behavior and the extinction and generalization of aversive memories in fear conditioning using a streptozotocin-induced model of diabetes (DBT). Moreover, considering that DBT animals present increased oxidative stress in brain areas related to anxiety and memory, we aimed to evaluate the effect of prolonged treatment with antioxidant vitamin E on behavioral parameters of anxiety and fear memory and on the diabetic condition. It was observed that DBT animals showed a deficiency in extinguishing the aversive memory in a fear conditioning test, along with a generalization of the fear memory. They also present a more pronounced anxiety-like behavior in the elevated plus maze test. VIT E treatment (300 mg/kg, p.o.) was not able to reduce hyperglycemia; however, it was able to block the anxiogenic-like behavior, also improving the deficit in the extinction of the aversive memory as well as blocking the generalization of such memory in a different context. Taken together, our data suggest that DBT animals are prone to extinction deficits and generalization of fear memories, behaviors which are observed in models of PTSD. Lastly, prolonged VIT E supplementation may be effective in the treatment of anxiety, extinction deficit and generalization of fear memories induced by the diabetic condition.

Ambrogini P, Torquato P, Bartolini D, Albertini MC, Lattanzi D, Di Palma M, Marinelli R, Betti M, Minelli A, Cuppini R, Galli F

Biochim Biophys Acta Mol Basis Dis. 2019 Jan 28. pii: S0925-4439(19)30032-8. doi: 10.1016/j.bbadis.2019.01.026. [Epub ahead of print]

Abstract

Glutamate-mediated excitotoxicity, neuroinflammation, and oxidative stress are common underlying events in neurodegeneration. This pathogenic “triad” characterizes the neurobiology of epilepsy, leading to seizure-induced cell death, increased susceptibility to neuronal synchronization and network alterations. Along with other maladaptive changes, these events pave the way to spontaneous recurrent seizures and progressive degeneration of the interested brain areas. In vivo models of epilepsy are available to explore such epileptogenic mechanisms, also assessing the efficacy of chemoprevention and therapy strategies at the pre-clinical level. The kainic acid model of pharmacological excitotoxicity and epileptogenesis is one of the most investigated mimicking the chronicization profile of temporal lobe epilepsy in humans. Its pathogenic cues include inflammatory and neuronal death pathway activation, mitochondrial disturbances and lipid peroxidation of several regions of the brain, the most vulnerable being the hippocampus. The importance of neuroinflammation and lipid peroxidation as underlying molecular events of brain damage was demonstrated in this model by the possibility to counteract the related maladaptive morphological and functional changes of this organ with vitamin E, the main fat-soluble cellular antioxidant and “conditional” co-factor of enzymatic pathways involved in polyunsaturated lipid metabolism and inflammatory signaling. The present review paper provides an overview of the literature supporting the potential for a timely intervention with vitamin E therapy in clinical management of seizures and epileptogenic processes associated with excitotoxicity, neuroinflammation and lipid peroxidation, i.e. the pathogenic “triad”.

Tamtaji OR, Taghizadeh M, Aghadavod E, Mafi A, Dadgostar E, Daneshvar Kakhaki R, Abolhassani J, Asemi Z

Clin Neurol Neurosurg. 2019 Jan;176:116-121. doi: 10.1016/j.clineuro.2018.12.006. Epub 2018 Dec 8.

Abstract

OBJECTIVE:

This study was conducted to evaluate the effects of omega-3 fatty acids and vitamin E co-supplementation on gene expression related to inflammation, insulin and lipid in subjects with Parkinson’s disease (PD).

PATIENTS AND METHODS:

This randomized, double-blind, placebo-controlled clinical trial was performed in 40 subjects with PD. Participants were randomly allocated into two groups to take either 1000 mg/day of omega-3 fatty acids from flaxseed oil plus 400 IU/day of vitamin E supplements or placebo (n = 20 each group) for 12 weeks. Gene expression related to inflammation, insulin and lipid were quantified in peripheral blood mononuclear cells (PBMC) of PD patients with RT-PCR method.

RESULTS:

After the 12-week intervention, compared with the placebo, omega-3 fatty acids and vitamin E co-supplementation downregulated gene expression of tumor necrosis factor alpha (TNF-α) (P = 0.002) in PBMC of subjects with PD. In addition, omega-3 fatty acids and vitamin E co-supplementation upregulated peroxisome proliferator-activated receptor gamma (PPAR-γ) (P = 0.03), and downregulated oxidized low-density lipoprotein receptor (LDLR) (P = 0.002) in PBMC of subjects with PD compared with the placebo. We did not observe any significant effect of omega-3 fatty acids and vitamin E co-supplementation on gene expression of interleukin-1 (IL-1) and IL-8 in PBMC of patients with PD.

CONCLUSIONS:

Overall, omega-3 fatty acids and vitamin E co-supplementation for 12 weeks in PD patients significantly improved gene expression of TNF-α, PPAR-γ and LDLR, but did not affect IL-1 and IL-8.

Sayyahi A, Jahanshahi M, Amini H, Sepehri H

Folia Neuropathol. 2018;56(3):215-228. doi: 10.5114/fn.2018.78703.

Abstract

M1 muscarinic receptor plays a fundamental role in memory and is closely associated with Alzheimer’s disease (AD); it has long been assumed as a therapeutic goal. By activating of the cholinergic receptor vitamin E helps with memory retention. But effects of vitamin E on density of M1 muscarinic receptor-immunoreactive (ir) neurons remain poorly understood. The present research aimed to examine the chronic administration effect of vitamin E against scopolamine-induced memory loss and the number of M1 muscarinic receptor-ir neurons of the hippocampus in male rats. Randomly, 42 adult male Wistar rats were divided to six groups: control, Sham-saline: receiving scopolamine + saline, Sham-sesame oil: receiving scopolamine + sesame oil and three experimental groups: receiving scopolamine + vitamin E with different doses (25, 50, and 100 mg/kg/day, i.p.) for 14 days. The passive avoidance task was used for the memory test. Twenty-four hours after behavioral tests, rats’ brains were taken and fixed, and after tissue processing, sections were stained using the immunohistochemical technique for M1 muscarinic receptor-ir neurons and cresyl violet for neurons. The injection of scopolamine to rats caused memory impairment and vitamin E treatment could ameliorate it. In the scopolamine-treated groups, the number of CA1 and CA3 pyramidal and dentate gyrus (DG) granular neurons was decreased significantly as compared to the control group. Vitamin E treatment significantly increased neuron numbers in the CA1 and CA3 areas of the hippocampus and DG area. Treatment with vitamin E for 14 days could compensate the loss of M1 muscarinic receptor-immunoreactive neuron numbers induced by scopolamine in the hippocampus. The most effective vitamin E dose was 50 mg/kg/day in this study. In conclusion, vitamin E can compensate the neuronal loss in the hippocampal formation and also it can raise the density of M1 receptor-ir muscarinic neurons after an injection of scopolamine.

Huang X, Zhang H, Zhen J, Dong S, Guo Y, Van Halm-Lutterodt N, Yuan L

Aging (Albany NY). 2018 Dec 20;10(12):4066-4083. doi: 10.18632/aging.101694.

Abstract

OBJECTIVE:

The current study evaluated the relationship between circulating fat soluble vitamin status and cognition in aging Chinese population.

METHODS:

A cross-sectional study was carried out in 1754 community residents aged 55-80 years aiming to evaluate the relationship between circulating α-tocopherol and retinol status and cognition. The effect of ApoE genetic polymorphism on the relationship between vitamins and cognition was also explored.

RESULTS:

Our results indicated that serum retinol status positively correlated with cognitive performance; while, serum α-tocopherol (α-TOH)/retinol ratio negatively correlated with cognitive performance. Mild cognitive impairment (MCI) subject demonstrated higher serum α-TOH status (P < 0.05), α-TOH/retinol ratio (P < 0.01) and lower retinol status (P < 0.01) than normal subjects. Subjects with ApoE4 genotype have lower serum retinol level (P < 0.05) and higher α-TOH/retinol ratio (P < 0.01) than subjects with ApoE3 genotype. MCI-ApoE4 carriers demonstrated the worst cognitive performance (P < 0.05) and exhibited higher serum TC, α-TOH and α-TOH/retinol ratio levels (P < 0.05), and lower LDL-C, retinol and lipid-adjusted retinol status (P < 0.05). MCI-ApoE2 subjects showed higher serum TC, HDL-C content and α-TOH/retinol ratio (P < 0.05); and lower serum retinol and lipid-adjusted retinol status (P < 0.05).

CONCLUSION:

Lower circulating retinol and higher α-TOH/retinol ratio potentially predicts an increased risk for the development of cognitive decline in aging Chinese adults. ApoE2 or E4 carriers with higher circulating α-TOH/retinol ratio infer poor cognitive performance and an increased risk of developing MCI.

Zingg JM

IUBMB Life. 2018 Dec 17. doi: 10.1002/iub.1986. [Epub ahead of print]

Abstract

Vitamin E modulates signal transduction pathways by several molecular mechanisms. As a hydrophobic molecule located mainly in membranes it contributes together with other lipids to the physical and structural characteristics such as membrane stability, curvature, fluidity, and the organization into microdomains (lipid rafts). By acting as the main lipid-soluble antioxidant, it protects other lipids such as mono- and poly-unsaturated fatty acids (MUFA and PUFA, respectively) against chemical reactions with reactive oxygen and nitrogen species (ROS and RNS, respectively) and prevents membrane destabilization and cellular dysfunction. In cells, vitamin E affects signaling in redox-dependent and redox-independent molecular mechanisms by influencing the activity of enzymes and receptors involved in modulating specific signal transduction and gene expression pathways. By protecting and preventing depletion of MUFA and PUFA it indirectly enables regulatory effects that are mediated by the numerous lipid mediators derived from these lipids. In recent years, some vitamin E metabolites have been observed to affect signal transduction and gene expression and their relevance for the regulatory function of vitamin E is beginning to be elucidated. In particular, the modulation of the CD36/FAT scavenger receptor/fatty acids transporter by vitamin E may influence many cellular signaling pathways relevant for lipid homeostasis, inflammation, survival/apoptosis, angiogenesis, tumorigenesis, neurodegeneration, and senescence. Thus, vitamin E has an important role in modulating signal transduction and gene expression pathways relevant for its uptake, distribution, metabolism, and molecular action that when impaired affect physiological and patho-physiological cellular functions relevant for the prevention of a number of diseases.