Long-term monotherapy treatment with vitamin E reduces oxidative stress, but not seizure frequency in rats submitted to the pilocarpine model of epilepsy

Pansani AP, Cysneiros RM, Colugnati DB, Janjoppi L, Ferrari D, de Lima E, Ghazale PP, Sinigaglia-Coimbra R, Scorza FA

Epilepsy Behav. 2018 Nov;88:301-307. doi: 10.1016/j.yebeh.2018.09.027. Epub 2018 Oct 17.

Abstract

The imbalance between antioxidant system and reactive oxygen species (ROS) generation is related to epileptogenesis, neuronal death, and seizure frequency. Treatment with vitamin E has been associated with neuroprotection and control of seizures. In most experimental studies, vitamin E treatment has short duration. Therefore, the aim of this study was to verify the role of long-term treatment with vitamin E in rats submitted to the pilocarpine model of epilepsy. Rats were divided into two main groups: control (Ctr) and pilocarpine (Pilo). Each one was subdivided according to treatment: vehicle (Ctr V and Pilo V) or vitamin E at dosages of 6 IU/kg/day (Ctr E6 and Pilo E6) or 60 IU/kg/day (Ctr E60 and Pilo E60). Treatment lasted 120 days from status epilepticus (SE). There were no statistical differences concerning treatment in the Ctr group for all variables, so the data were grouped. Carbonyl content in the hippocampus of Pilo V and Pilo E6 was higher compared with that of the Ctr group (8 ± 1.5, 7.1 ± 1, and 3.1 ± 0.3 nmol carbonyl/mg protein, respectively for Pilo V, Pilo E6, and Ctr; p < 0.05). Carbonyl content was restored to control values in Pilo E60 rats (4.2 ± 1.1 and 3.1 ± 0.3 nmol carbonyl/mg protein, respectively for Pilo E60 and Ctr; p > 0.05). The volume of the hippocampal formation (6.5 ± 0.3, 6.6 ± 0.4, 6.3 ± 0.3, and 7.4 ± 0.2, respectively for Pilo V, Pilo E6, Pilo E60, and Ctr) and subfields CA1 (1.6 ± 0.1, 1.4 ± 0.2, 1.5 ± 0.1, and 2 ± 0.05, respectively for Pilo V, Pilo E6, Pilo E60, and Ctr) and CA3 (1.7 ± 0.1, 1.5 ± 0.2, 1.4 ± 0.1, and 2 ± 0.1, respectively for Pilo V, Pilo E6, Pilo E60, and Ctr) was reduced in the Pilo group regardless of treatment. Parvalbumin immunostaining was increased in the hilus of the Pilo E60 group compared with that in the Ctr group (26 ± 2 and 39.6 ± 8.3 neurons, respectively for Ctr and Pilo E60). No difference was found in seizure frequency and Neo-Timm staining. Therefore, long-term treatment with 60 IU/kg/day of vitamin E prevented oxidative damage in the hippocampus and increased hilar parvalbumin expression in rats with epilepsy without a reduction in seizure frequency.

Taylor L, Krueger N, Malysheva O, Atkinson J, Parker RS

Bioorg Med Chem. 2018 Nov 1;26(20):5555-5565. doi: 10.1016/j.bmc.2018.10.002. Epub 2018 Oct 5.

Abstract

α-Tocopherol (α-TOH) is the primary lipophilic radical trapping antioxidant in human tissues. Oxidative catabolism of α-tocopherol (αTOH) is initiated by ω-hydroxylation of the terminal carbon (C-13) of the isoprenoid sidechain followed by oxidative transformations that sequentially truncate the chain to yield the 2,5,7,8-tetramethyl(3’carboxyethyl)-6-hydroxychroman (α-CEHC). After conjugation to glucuronic acid, 3′-carboxyethyl-6-hydroxychroman glucuronide is excreted in urine. We report here that the same enzyme that accomplishes this task, the cytochrome P450 monooxygenase CYP-4F2, can also ω-hydroxylate the terminal carbon of α-tocopheryl quinone. A standard sample of ω-OH-α-tocopheryl quinone (ω-OH-α-TQ) was synthesized as a mixture of stereoisomers by allylic oxidation of α-tocotrienol using SeO₂followed by double-bond reduction and oxidation to the quinone. After incubating human liver microsomes or insect cell microsomes expressing only recombinant human CYP-4F2, cytochrome b5, and NADPH P450 reductase with d₆-α-tocopheryl quinone (d₆-αTQ), we showed that the ω-hydroxylated (13-OH) d₆-α-TQ was produced. We further identified the production of the terminal carboxylic acid d₆-13-COOH-αTQ. The ramifications of this discovery to the understanding of tocopherol utilization and metabolism, including the quantitative importance of the αTQ-ω-hydroxylase pathway in humans, are discussed.

Lee GY, Han SN

Nutrients. 2018 Nov 1;10(11). pii: E1614. doi: 10.3390/nu10111614.

Abstract

Vitamin E is a fat-soluble antioxidant that can protect the polyunsaturated fatty acids (PUFAs) in the membrane from oxidation, regulate the production of reactive oxygen species (ROS) and reactive nitrogen species (RNS), and modulate signal transduction. Immunomodulatory effects of vitamin E have been observed in animal and human models under normal and disease conditions. With advances in understating of the development, function, and regulation of dendritic cells (DCs), macrophages, natural killer (NK) cells, T cells, and B cells, recent studies have focused on vitamin E‘s effects on specific immune cells. This review will summarize the immunological changes observed with vitamin Eintervention in animals and humans, and then describe the cell-specific effects of vitamin E in order to understand the mechanisms of immunomodulation and implications of vitamin E for immunological diseases.

Li M, Zhang E, Lü L, Ban W, Dang X, Zhang C

Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi. 2018 Nov 1;32(11):1421-1428. doi: 10.7507/1002-1892.201801046.

Abstract

OBJECTIVE:

To investigate the possibility of mitochondria-dependent apoptosis as a mechanism of early steroid-induced avascular necrosis of femoral head (SANFH) in rats and vitamin E as a possible prevention strategy.

METHODS:

Seventy-two male Sprague Dawley rats were randomly divided into control group, model group, and intervention group, with 24 rats in each group. The rats in control group were not treated as normal control. The rats in model group and intervention group were established early SANFH models by lipopolysaccharide combined with methylprednisolone injection. At the same time, the rats in intervention group were injected with vitamin E (40 mg/kg) every day for 7 days. At 2, 4, and 8 weeks after the final injection, the bilateral femoral heads were harvested and observed by HE staining, TUNEL assay, immunohistochemical staining, and Western blot. The rate of empty lacunae, apoptotic index, and the expressions of Caspase-9, Caspase-3, and cytochrome-c (Cyt-c) proteins were calculated.

RESULTS:

According to histological staining, there were significant differences in the rate of empty lacunae between intervention group and control group at 8 weeks ( P<0.05) and between intervention group and model group at 4 and 8 weeks ( P<0.05). The apoptotic index of intervention group was significantly lower than that of model group at each time point ( P<0.05). And there was significant difference between the intervention group and the control group at 8 weeks ( P<0.05). According to immunohistochemistry staining and Western blot, the expressions of Cyt-c, Caspase-9, and Caspase-3 all significantly decreased in intervention group than those in model group at each time point ( P<0.05); and the differences were significant between intervention group and control group at 8 weeks ( P<0.05).

CONCLUSION:

Vitamin E can delay the progression of early SANFH by reducing mitochondrial dependent osteocyte apoptosis.

Fayez AM, Zaafan MA

Arch Iran Med. 2018 Nov 1;21(11):502-508.

Abstract

BACKGROUND:

The current study aimed to evaluate the mechanisms involved in protection against doxorubicin-induced cardiac and renal toxicities upon treatment with eicosapentaenoic acid and vitamin E.

METHODS:

Rats were randomly assigned to 4 groups: normal control, doxorubicin inducted control, eicosapentaenoic acid treated group and a final group pretreated with vitamin E. Lipid peroxidation, reduced glutathione (GSH) and tumor necrosis factor-alpha (TNF-α) contents as well as glutathione peroxidase (GPx), superoxide dismutase (SOD) and myeloperoxidase (MPO) activities were assessed. Moreover, hearts were used for immunohistochemical detection of the pro-apoptotic protein cytochrome c expression, while the kidneys were used for detection of inducible nitric oxide synthase (iNOS) expression.

RESULTS:

Eicosapentaenoic acid and vitamin E produced significant protection from doxorubicin-induced cardiac and renal toxicities. The suggested mechanisms for protection included decreased cytochrome c and iNOS expression as well as markedly decreased lipid peroxides and TNF-α contents accompanied with increased GSH content as compared to the doxorubicin control group. Moreover, there was marked increase in GPx and SOD activities accompanied by significant suppression of MPO activity.

CONCLUSION:

The present study demonstrated the potent protective effects of eicosapentaenoic acid and vitamin E from doxorubicin induced cardiac and renal toxicities through their potent anti-oxidant, anti-inflammatory and anti-apoptotic properties. Hence, eicosapentaenoic acid and vitamin E could be promising protective agents against doxorubicintoxicity.

Nagib MM, Tadros MG, Rahmo RM, Sabri NA, Khalifa AE, Masoud SI

Neurotox Res. 2018 Oct 29. doi: 10.1007/s12640-018-9971-6. [Epub ahead of print]

Abstract

Phenytoin is one of the most well-known antiepileptic drugs that cause cognitive impairment which is closely related to cAMP response element-binding protein (CREB) brain-derived neurotrophic factor (BDNF) signaling pathway. Moreover, vascular endothelial growth factor (VEGF), an endothelial growth factor, has a documented role in neurogenesis and neuronal survival and cognitive impairment. Therefore, this study aimed to investigate the influence of powerful antioxidants: α-Toc and CoQ10 alone or combined in the preservation of brain tissues and the maintenance of memory formation in phenytoin-induced cognitive impairment in rats. The following behavioral test novel object recognition and elevated plus maze were assessed after 14 days of treatment. Moreover, VEGF, BDNF, TrkB, and CREB gene expression levels in the hippocampus and prefrontal cortex were estimated using RT-PCR. Both α-Toc and CoQ10 alone or combined with phenytoin showed improvement in behavioral tests compared to phenytoin. Mechanistically, α-Toc and/or CoQ10 decreases the VEGF mRNA expression, while increases BDNF-TrKB-CREB mRNA levels in hippocampus and cortex of phenytoin-treated rats. Collectively, α-Toc and/or CoQ10 alleviated the phenytoin-induced cognitive impairment through suppressing oxidative damage. The underlying molecular mechanism of the treating compounds is related to the VEGF and enhancing BDNF-TrkB-CREB signaling pathway. Our study indicated the usefulness α-Toc or CoQ10 as an adjuvant to antiepileptic drugs with an advantage of preventing cognitive impairment and oxidative stress.

Tang B, Qian Y, Gou Y, Cheng G, Fang G

Molecules. 2018 Oct 25;23(11). pii: E2760. doi: 10.3390/molecules23112760.

Abstract

Multi-drug resistance (MDR) presents a serious problem in cancer chemotherapy. In this study, Vitamin E (VE)-Albumin core-shell nanoparticles were developed for paclitaxel (PTX) delivery to improve the chemotherapy efficacy in an MDR breast cancer model. The PTX-loaded VE-Albumin core-shell nanoparticles (PTX-VE NPs) had small particle sizes (about 100 nm), high drug entrapment efficiency (95.7%) and loading capacity (12.5%), and showed sustained release profiles, in vitro. Docking studies indicated that the hydrophobic interaction and hydrogen bonds play a significant role in the formation of the PTX-VE NPs. The results of confocal laser scanning microscopy analysis demonstrated that the cell uptake of PTX was significantly increased by the PTX-VE NPs, compared with the NPs without VE (PTX NPs). The PTX-VE NPs also exhibited stronger cytotoxicity, compared with PTX NPs with an increased accumulation of PTX in the MCF-7/ADR cells. Importantly, the PTX-VE NPs showed a higher anti-cancer efficacy in MCF-7/ADR tumor xenograft model than the PTX NPs and the PTX solutions. Overall, the VE-Albumin core-shell nanoparticles could be a promising nanocarrier for PTX delivery to improve the chemotherapeutic efficacy of MDR cancer.

Hagan ML, Bahraini A, Pierce JL, Bass SM, Yu K, Elsayed R, Elsalanty M, Johnson MH, McNeil A, McNeil PL, McGee-Lawrence ME

Calcif Tissue Int. 2018 Oct 24. doi: 10.1007/s00223-018-0487-0. [Epub ahead of print]

Abstract

Osteocytes experience plasma membrane disruptions (PMD) that initiate mechanotransduction both in vitro and in vivo in response to mechanical loading, suggesting that osteocytes use PMD to sense and adapt to mechanical stimuli. PMD repair is crucial for cell survival; antioxidants (e.g., alpha-tocopherol, also known as Vitamin E) promote repair while reactive oxygen species (ROS), which can accumulate during exercise, inhibit repair. The goal of this study was to determine whether depleting Vitamin E in the diet would impact osteocyte survival and bone adaptation with loading. Male CD-1 mice (3 weeks old) were fed either a regular diet (RD) or Vitamin E-deficient diet (VEDD) for up to 11 weeks. Mice from each dietary group either served as sedentary controls with normal cage activity, or were subjected to treadmill exercise (one bout of exercise or daily exercise for 5 weeks). VEDD-fed mice showed more PMD-affected osteocytes (+ 50%) after a single exercise bout suggesting impaired PMD repair following Vitamin E deprivation. After 5 weeks of daily exercise, VEDD mice failed to show an exercise-induced increase in osteocyte PMD formation, and showed signs of increased osteocytic oxidative stress and impaired osteocyte survival. Surprisingly, exercise-induced increases in cortical bone formation rate were only significant for VEDD-fed mice. This result may be consistent with previous studies in skeletal muscle, where myocyte PMD repair failure (e.g., with muscular dystrophy) initially triggers hypertrophy but later leads to widespread degeneration. In vitro, mechanically wounded MLO-Y4 cells displayed increased post-wounding necrosis (+ 40-fold) in the presence of H₂O₂, which could be prevented by Vitamin E pre-treatment. Taken together, our data support the idea that antioxidant-influenced osteocyte membrane repair is a vital aspect of bone mechanosensation in the osteocytic control of PMD-driven bone adaptation.