Development of a novel squalene/α-tocopherol-based self-emulsified nanoemulsion incorporating Leishmania peptides for induction of antigen-specific immune responses

Vaccination has emerged as the most effective strategy to confront infectious diseases, among which is leishmaniasis, that threat public health. Despite laborious efforts there is still no vaccine for humans to confront leishmaniasis. Multi-epitope protein/peptide vaccines present a number of advantages, however their use along with appropriate adjuvants that may also act as antigen carriers is considered essential to overcome subunit vaccines' low immunogenicity. In the present study, a stable self-emulsified nanoemulsion was developed and double-adjuvanted with squalene and α-tocopherol. The prepared nanoemulsion droplets exhibited low cytotoxicity in a certain range of concentrations, while they were efficiently taken up by macrophages and dendritic cells in vitro as well as in vivo in secondary lymphoid organs. To further characterize nanoformulation's potent antigen delivery capability, three multi-epitope Leishmania peptides were incorporated into the nanoemulsion. Peptide encapsulation resulted in dendritic cells' functional differentiation characterized by elevated levels of maturation markers and intracellular cytokine production. Intramuscular administration of the nanoemulsion incorporating Leishmania peptides induced antigen-specific spleen cell proliferation as well as elicitation of CD4+ central memory cells, supporting the potential of the developed nanoformulation to successfully act also as an antigen delivery vehicle and thus encouraging further preclinical studies on its vaccine candidate potency.

Zinc and α-tocopherol protect the antral follicles and endogenous antioxidants of female albino rats (Rattus norvegicus) against lead toxicity

BACKGROUND

Lead impairs female reproductive health because it can induce oxidative stress. Zinc as an antioxidant produces an enzyme system that helps neutralize free radicals. α-Tocopherol has an antagonistic effect that reduces oxidative stress. This study aimed to demonstrate the effects of zinc (Zn) and α-tocopherol on the ovarian endogenous antioxidants and antral follicles of albino rats (Rattus norvegicus) exposed to lead acetate (Pb(C2H3O2)2).

METHODS

Twenty-five female Wistar rats were divided into five groups, namely groups K (control), P0, P1, P2, and P3. Following exposure and treatment for 21 days with different combinations, the albino rats were necropsied, and their ovaries were removed for subsequent histopathological preparations and endogenous antioxidant analysis. Observations were made on the ovary, including an antral follicle count and diameter calculations. Analysis of the superoxide dismutase (SOD) levels (560 nm wavelength) and malondialdehyde MDA-TBA (532 nm wavelength) were performed by a spectrophotometer. The data were analyzed using a one-way ANOVA and least significant difference (LSD) test with the SPSS V24 software.

RESULTS

The highest SOD enzyme expression in the albino rat ovaries was in P0 (17.23 ± 5.34), and the lowest was in P3 (4.21 ± 0.76). The lowest MDA level was observed in the control group (K) and P3 compared to the other groups. The highest average antral follicle count and diameter were found in the albino rats exposed to 1.5 mg/kg BW lead acetate, and treated with 0.54 mg/kg BW zinc sulfate and 100 mg/kg BW α-tocopherol (group P3) compared to the other groups. The mechanisms of action of zinc and α-tocopherol work synergistically to decrease free radicals and ovarian damage.

CONCLUSION

The results showed that a combination of 0.54 mg/kg BW zinc (Zn) and 100 mg/kg BW α-tocopherol can maintain the number and diameter of the antral follicles and reduce ovarian SOD expression and MDA levels in albino rats exposed to lead acetate.

Synergistic effect of chitosan-alginate composite hydrogel enriched with ascorbic acid and alpha-tocopherol under hypoxic conditions on the behavior of mesenchymal stem cells for wound healing

BACKGROUND

In regenerative medicine, especially skin tissue engineering, the focus is on enhancing the quality of wound healing. Also, several constructs with different regeneration potentials have been used for skin tissue engineering. In this study, the regenerative properties of chitosan-alginate composite hydrogels in skin wound healing under normoxic and hypoxic conditions were investigated in vitro.

METHODS

The ionic gelation method was used to prepare chitosan/alginate (CA) hydrogel containing CA microparticles and bioactive agents [ascorbic acid (AA) and α-tocopherol (TP)]. After preparing composite hydrogels loaded with AA and TP, the physicochemical properties such as porosity, pore size, swelling, weight loss, wettability, drug release, and functional groups were analyzed. Also, the hemo-biocompatibility of composite hydrogels was evaluated by a hemolysis test. Then, the rat bone marrow mesenchymal stem cells (rMSCs) were seeded onto the hydrogels after characterization by flow cytometry. The survival rate was analyzed using MTT assay test. The hydrogels were also investigated by DAPI and H&E staining to monitor cell proliferation and viability. To induce hypoxia, the cells were exposed to CoCl2. To evaluate the regenerative potential of rMSCs cultured on CA/AA/TP hydrogels under hypoxic conditions, the expression of the main genes involved in the healing of skin wounds, including HIF-1α, VEGF-A, and TGF-β1, was investigated by real-time PCR.

RESULTS

The results demonstrated that the prepared composite hydrogels were highly porous, with interconnected pores that ranged in sizes from 20 to 188 μm. The evaluation of weight loss showed that the prepared hydrogels have the ability to biodegrade according to the goals of wound healing. The reduction percentage of CA/AA/TP mass in 21 days was reported as 21.09 ± 0.52%. Also, based on wettability and hemolysis tests of the CA/AA/TP, hydrophilicity (θ = 55.6° and 53.7°) and hemocompatibility with a hemolysis ratio of 1.36 ± 0.19 were evident for them. Besides, MTT assay, DAPI, and H&E staining also showed that the prepared hydrogels provide a suitable substrate for cell growth and proliferation. Finally, based on real-time PCR, increased expression levels of VEGF and TGF-β1 were observed in rMSCs in hypoxic conditions cultured on the prepared hydrogels.

CONCLUSIONS

In conclusion, this study provides evidence that 3D CA/AA/TP composite hydrogels seeded by rMSCs in hypoxic conditions have great potential to improve wound healing.

Antioxidant nanoemulsion loaded with latanoprost enables highly effective glaucoma treatment

Glaucoma is the third leading cause of blindness worldwide and is primarily characterized by elevated intraocular pressure (IOP). Common risk factors such as age, myopia, ocular trauma, and hypertension all increase the risk of elevated IOP. Prolonged high IOP not only causes physiological discomfort like headaches, but also directly damages retinal cells and leads to retinal ischemia, oxidative imbalance, and accumulation of reactive oxygen species (ROS) in the retina. This oxidative stress causes the oxidation of proteins and unsaturated lipids, leading to peroxide formation and exacerbating retinal damage. While current clinical treatments primarily target reducing IOP through medication or surgery, there are currently no effective methods to mitigate the retinal cell damage associated with glaucoma. To address this gap, we developed a novel nanoemulsion to co-delivery latanoprost and α-tocopherol (referred to as LA@VNE later) that prolongs ocular retention and enhances retinal permeability through localized administration. By encapsulating latanoprost, an IOP-lowering drug, and α-tocopherol, a potent antioxidant, we effectively reduced ROS accumulation (>1.5-fold in vitro and 2.5-fold in vivo), retinal ganglion cell (RGC) apoptosis (>9 fold), and inflammatory cell infiltration (>1.6 fold). Our approach showed strong biocompatibility and significant potential for clinical translation, providing a promising platform for the treatment of glaucoma.

7β-Hydroxycholesterol and 7-ketocholesterol: New oxidative stress biomarkers of sarcopenia inducing cytotoxic effects on myoblasts and myotubes

Aging is a complex biological process which can be associated with skeletal muscle degradation leading to sarcopenia. The aim of this study consisted i) to determine the oxidative and inflammatory status of sarcopenic patients and ii) to clarify the impact of oxidative stress on myoblasts and myotubes. To this end, various biomarkers of inflammation (C-reactive protein (CRP), TNF-α, IL-6, IL-8, leukotriene B4 (LTB4)) and oxidative stress (malondialdehyde, conjugated dienes, carbonylated proteins and antioxidant enzymes: catalase, superoxide dismutase, glutathione peroxidase) as well as oxidized derivatives of cholesterol formed by cholesterol autoxidation (7-ketocholesterol, 7β-hydroxycholesterol), were analyzed. Apelin, a myokine which contributes to muscle strength, was also quantified. To this end, a case-control study was conducted to evaluate the RedOx and inflammatory status in 45 elderly subjects (23 non-sarcopenic; 22 sarcopenic) from 65 years old and higher. SARCopenia-Formular (SARC-F) and Timed Up and Go (TUG) tests were used to distinguish between sarcopenic and non-sarcopenic subjects. By using red blood cells, plasma and/or serum, we observed in sarcopenic patients an increased activity of major antioxidant enzymes (superoxide dismutase, glutathione peroxidase, catalase) associated with lipid peroxidation and protein carbonylation (increased level of malondialdehyde, conjugated dienes and carbonylated proteins). Higher levels of 7-ketocholesterol and 7β-hydroxycholesterol were also observed in the plasma of sarcopenic patients. Significant differences were only observed with 7β-hydroxycholesterol. In sarcopenic patients comparatively to non-sarcopenic subjects, significant increase of CRP, LTB4 and apelin were observed whereas similar levels of TNF-α, IL-6 and IL-8 were found. The increased plasma level of 7-ketocholesterol and 7β-hydroxycholesterol in sarcopenic patients led us to study the cytotoxic effect of these oxysterols on undifferentiated (myoblasts) and differentiated (myotubes) murine C2C12 cells. With the fluorescein diacetate and sulforhodamine 101 assays, an induction of cell death was observed both on undifferentiated and differentiated cells: the cytotoxic effects were less pronounced with 7-ketocholesterol. In addition, IL-6 secretion was never detected whatever the culture conditions, TNF-α secretion was significantly increased on undifferentiated and differentiated C2C12 cells treated with 7-ketocholesterol- and 7β-hydroxycholesterol, and IL-8 secretion was increased on differentiated cells. 7-ketocholesterol- and 7β-hydroxycholesterol-induced cell death was strongly attenuated by α-tocopherol and Pistacia lentiscus L. seed oil both on myoblasts and/or myotubes. TNF-α and/or IL-8 secretions were reduced by α-tocopherol and Pistacia lentiscus L. seed oil. Our data support the hypothesis that the enhancement of oxidative stress observed in sarcopenic patients could contribute, especially via 7β-hydroxycholesterol, to skeletal muscle atrophy and inflammation via cytotoxic effects on myoblasts and myotubes. These data bring new elements to understand the pathophysiology of sarcopenia and open new perspectives for the treatment of this frequent age-related disease.

α-Tocopherol application as a countermeasure to UV-B stress in bread wheat (Triticum aestivum L.)

The source of energy for all photoautotrophic organisms is light, which is absorbed by photosynthetic processes and used to transform carbon dioxide and H2O into organic molecules. The majority of UV-B light (280 to 320 nm) is absorbed by stratospheric ozone layer, although some of it does reach at the Earth's surface. Because of the sedentary lifestyle of plants, this form of abiotic stress is unavoidable and can induce growth and even cell death. Ten-day-old calli generated from mature Kirik wheat embryos were subjected to UV-B radiation for 0, 2, 4, and 6 h to examine the function of exogenous α-tocopherol, a lipophilic antioxidant, in wheat tolerance to UV-B radiation stress. The calli were then moved to a callus medium containing α-tocopherol (0, 50, and 100 mg/l) and cultivated there for 20 days after being subjected to UV-B stress. For plant regeneration, embryogenic calli were put on a medium for plant regeneration after 30 days. The findings of this investigation demonstrated that an increase in UV-B exposure period resulted in a substantial drop in the relative growth rate of callus, the rate of embryogenic callus, the rate of responding embryogenic callus, and the number of plants in each explant. On the other hand, with the application of α-tocopherol, all these parameters improved, and the best result was observed in the application of 100 mg/l of α-tocopherol in terms of plant regeneration under UV-B stress.

α-tocopherol ameliorates copper II oxide nanoparticles-induced cytotoxic, biochemical, apoptotic, and genotoxic damages in the rainbow trout gonad cells-2 (RTG-2) culture

We investigated the effects of α-tocopherol on oxidative stress-caused damage caused by copper II oxide nanoparticles (CuO NPs) on Oncorhynchus mykiss gonadal cells (RTG-2) for 24 and 48 h. α-Tocopherol reversed the cell death and alterations in the expressions of genes such as sod1, gpx1a, gpx4b, and igf2 caused by CuO NPs; it also supported the expressions of cat, igf1, and gapdh genes caused by CuO NPs for 24 h and promoted alterations in the expressions of the sod2, gh1, and igf1 genes for 48 h. Additionally, α-tocopherol reversed the caspase 3/7 activity increased by CuO NPs for 24 h and supported it's decrease for 48 h. α-Tocopherol supported the increase in tail DNA (%) affected by CuO NPs for 24 h and reversed it for 48 h. Therefore, α-tocopherol may have the potential to protect against cellular alterations induced by CuO NPs in a time-dependent manner.

Solubilization of α-tocopherol and curcumin by polyoxyethylene alkyl ether surfactants: Effect of alkyl chain structure

The effects of the structural characteristics of the alkyl chains of polyoxyethylene alkyl ether-type surfactants (Brij) on the solubilization of α-tocopherol and curcumin by surfactant micelles were investigated: Brij L23 (lauryl; C_12:0); S20 (stearyl; C_18:0); and Brij O20 (oleyl; C_18:1). When α-tocopherol or curcumin were solubilized in Brij micelle solutions below their maximum solubilization concentrations (C_max), the Brij L23 micelles exhibited the largest increase in dimensions due to the presence of the guest molecules. Above C_max, excess α-tocopherol existed as microemulsion droplets whereas excess curcumin existed as insoluble crystals. Our results suggest that the guest molecules were preferentially located within the palisade layers of micelles, which can be attributed to the fact that they contained bother polar and non-polar moieties. These results may be important for the formulation of colloidal delivery systems to encapsulate and deliver oil-soluble vitamins and nutraceuticals.

Insights into the binding mechanism between α-TOH and CYP4F2: A homology modeling, molecular docking, and molecular dynamics simulation study

α-Tocopherol (α-TOH) is a potent antioxidant. The concentrations of α-TOH in plasma are closely related to human health. α-TOH can be regulated by the metabolism of cytochrome P450 4F2 (CYP4F2). However, the atomic-level basis for this regulation process remains elusive. Here, we successfully constructed the structure of CYP4F2 by homology modeling and obtained the α-TOH-CYP4F2 complex models using molecular docking. Three parallel 500 ns molecular dynamics simulations were performed on each complex model to investigate the details of the interaction between α-TOH and CYP4F2. MM-GBSA method combined with principal component analysis shows that 8 key residues establish a hydrophobic cavity stabilizing α-TOH in the pocket of CYP4F2 and S423 forms an important hydrogen bond with α-TOH anchoring α-TOH in the favorable position for ω-hydroxylation. Based on our simulation results and the experimental facts, we designed mutation simulation experiments to clarify the important role of two key residues (S423 and V433) in the binding of α-TOH with CYP4F2. The results show that the mutations directly or indirectly change the binding mode of α-TOH and decrease its binding affinity with CYP4F2, which is unfavorable for ω-hydroxylation. Our results could enrich the information on structure-function relationships of CYP4F2 and provide valuable insights into the regulatory mechanism of CYP4F2 on the metabolism of α-TOH.

Natural Vitamin E Supplementation during Pregnancy in Rats Increases RRR-α-Tocopherol Stereoisomer Proportion and Enhances Fetal Antioxidant Capacity, Compared to Synthetic Vitamin E Administration

INTRODUCTION

Low dietary intake of vitamin E is a global public health issue. RRR-α-tocopherol (RRR-αT) is the only naturally occurring vitamin E stereoisomer, but the equimolecular mixture of all eight stereoisomers, synthetic vitamin E (S-αT), is commonly consumed. The objective of this study was to evaluate bioavailability and antioxidant activity of RRR-αT versus S-αT, in both mother and fetus, after maternal supplementation during pregnancy.

METHODS

Female rats (7 weeks of age) received a modified AIN-93G diet supplemented with 75 IU/kg of RRR-αT (NVE, n = 20) or S-αT (SVE, n = 17). At delivery, the levels of αT, stereoisomer distribution, and antioxidant capacity were analyzed in maternal and fetal plasma.

RESULTS

NVE administration significantly increased the proportion of RRR-αT stereoisomer in maternal and fetal plasma. The percentage of RRR-αT increased from 32.76% to 88.33% in maternal plasma, and 35.25% to 97.94% in fetal plasma, in the NVE group compared to SVE. Fetal plasma from the NVE group was found to have higher total antioxidant capacity compared to SVE. Lastly, fetal plasma RRR-αT stereoisomer percentage was positively associated with expression levels of scavenger receptor class B type 1 (SR-B1) in the placenta.

CONCLUSIONS

Both natural and synthetic sources of vitamin E showed similar bioavailability. Still, NVE supplementation increased the proportion of RRR-αT and promoted higher antioxidant activity in fetal plasma at birth. Placental SR-B1 might be involved in the stereoselective transfer of RRR-αT stereoisomer across the placenta and may improve αT bioactivity in the fetus.

Pre- and post-treatment of α-Tocopherol on cognitive, synaptic plasticity, and mitochondrial disorders of the hippocampus in icv-streptozotocin-induced sporadic Alzheimer's-like disease in male Wistar rat

Objective

Most dementia cases in the elderly are caused by Alzheimer's disease (AD), a complex, progressive neurological disease. Intracerebroventricular (ICV) administration of streptozotocin (STZ) in rat's results in aberrant brain insulin signaling, oxidative stress, and mitochondrial dysfunction that impair cognition change neural plasticity, and eventually lead to neuronal death. The current study aims to define the neuroprotective action of alpha-tocopherol in enhancing mitochondrial function and the function of synapses in memory-impaired rats brought on by icv-STZ.

Methods

Male Wistar rats were pre-treated with (α-Tocopherol 150 mg/kg) orally once daily for 7 days before and 14 days after being bilaterally injected with icv-STZ (3 mg/kg), while sham group rats received the same volume of STZ solvent. After 2 weeks of icv-STZ infusion, rats were tested for cognitive performance using a behaviors test and then were prepared electrophysiology recordings or sacrificed for biochemical and histopathological assays.

Results

The cognitive impairment was significantly minimized in the behavioral paradigms for those who had taken α-Tocopherol. In the hippocampus of icv-STZ rat brains, α-Tocopherol ocopherol effectively prevented the loss of glutathione levels and superoxide dismutase enzyme activity, lowered mitochondrial ROS and mitochondrial membrane potential, and also brought about a decrease in Aβ aggregation and neuronal death.

Conclusion

Our findings demonstrated that by lowering neurobehavioral impairments caused by icv-STZ, oxidative stress, and mitochondrial dysfunction, α-Tocopherol enhanced intracellular calcium homeostasis and corrected neurodegenerative defects in the brain. These findings examine the available approach for delaying AD connected to mitochondrial malfunction and plasticity issues.

Establishing preanalytical stability of vitamin A and vitamin E

Vitamin A and Vitamin E, a group of lipid-soluble vitamins, can be degraded by photolysis and photooxidation after exposure to light. As an essential area of the preanalytical stage, inappropriate storage conditions of patient samples could lead to inaccurate results. In this study, we evaluated three of the most common preanalytical storage conditions (RT, +4°C, and -20 °C) in the workflow in the clinical laboratory setting using both clear and amber Eppendorf tubes. Analyte stability in each storage condition was tested with five patient pools. After 24 hrs at RT, a significant decrease in vitamin A and E was observed for samples stored in clear Eppendorf tubes (19.2 % and 17.9 %, for vitamin A and E, respectively), compared with samples stored in amber Eppendorf tubes (9.1 % and 7.3 %), respectively. After the specimen was stored at 4 °C for 7 days, vitamin A concentrations decreased in clear tubes by 14.7 % and in amber tubes by 12.7 %. Similarly, vitamin E concentrations decreased in both clear and amber tubes by 11.2 % and 13.4 %, respectively. Both vitamin A and vitamin E demonstrated acceptable stability in clear and amber Eppendorf tubes at -20 °C for up to 22 days. It is preferable to use amber tubes to protect vitamin A and E from light during short term storage. Storage of vitamin A and E specimens beyond 7 days should be at -20 °C.

Cholesterol accumulation in hepatocytes mediates IRE1/p38 branch of endoplasmic reticulum stress to promote nonalcoholic steatohepatitis

Non-alcoholic fatty liver disease (NAFLD), based on the elevating obesity incidence, is one of the major health issue worldwide. Transition from NAFLD to non-alcoholic steatohepatitis (NASH) is driven by increased apoptosis and is relevant to higher morbidity rates. In regard to limited understanding on cholesterol mediated hepatocyte alterations in NALFD/NASH transition, we investigated endoplasmic reticulum (ER) stress and related apoptosis. Our findings suggest that cholesterol upregulates ER stress and enhances C/EBP homologous protein (CHOP) either in hypercholesterolemic rabbits or in hepatocytes treated with liposome-cholesterol complex. Mechanistically, cholesterol accumulation in hepatocytes activates IRE1/p38 branch of ER stress, stimulating CHOP levels. In liver tissues of cholesterol fed rabbits, α-tocopherol supplementation decreased IRE1/p38/CHOP activation and prevented NASH development. Thus, our study provides a critical role of hepatocyte cholesterol in inducing IRE1/p38/CHOP pathway and suggests novel candidates for therapeutic targets against NASH.

The possible effects of α-tocopherol against amiodarone-treated lungs in rats: vimentin detection, lipid peroxidation assay, and histological and ultrastructural evaluations

The purpose of this study was to learn more about the pathogenesis of amiodarone (AD) on alveoli and also the possible preventive effect of α-tocopherol (α-T) against these hazards. Rats were divided into 4 groups, one of which acted as a control, the second received α-T, the third AD, and the fourth AD and α-T for 2 weeks. Light microscopy (LM), immunohistochemistry, transmission electron microscopy (TEM), and malondialdehyde (MDA) activity were analyzed in sections of lung tissue. Alveoli of lung tissue AD examined with LM showed dilatation of alveolar spaces, aggregation of red blood cells, and narrowing of alveolar septa. When stained with vimentin (VIM), alveoli showed a positive reaction in the majority and a moderate reaction in others. In the pneumocytes of the type II, some cytoplasmic vesicles had been deflated, whereas others contained lamellar bodies, a damaged nucleus, and vesicles in their heterochromatin. In the interstitial space, collagen fibers with aggregation of red blood cells and a disrupted blood-air barrier were detected. In rat lung alveoli treated with AD and α-T, the alveolar septum thickened and the alveolar spaces expanded as estimated. The alveoli of this group had more or less intact type I and II pneumocytes and a better appearance of the blood-air barrier. In the cells of the alveolar lining, the VIM staining leads to a diffuse positive response. Finally, lung parenchyma also improved, suggesting that α-T may help minimize the effects of AD.

Tocopherol Accumulation and Temporal Expression Analysis of VTE1 and VTE5 Gene Family in Fruit of Two Contrasting Avocado Genotypes

α-tocopherol is found in high concentrations in avocado fruit mesocarp, however, its accumulation and genetic control during maturation and ripening has not been elucidated. Based in the relevance of VTE1 and VTE5 genes in tocopherol biosynthesis and aiming to determine the association between tocopherol accumulation and expression of tocopherol biosynthetic genes, gene expression of VTE1 and VTE5 were evaluated through the time during three developmental stages: before harvest at 100, 160 and 220 days after flowering (DAF) and after harvest (220 DAF + 5) in two contrasting avocado genotypes (San Miguel and AVO40). San Miguel reached the highest levels at 220 DAF, whereas AVO40 increased α-tocopherol only after ripening (220 DAF + 5). A genome-wide search for VTE1 and VTE5 allowed to identify one and three genes, respectively. Both genotypes showed contrasting patterns of gene expression. Interestingly, AVO40 showed a highly positive correlation between α-tocopherol levels and gene expression of VTE1 and all VTE5 variants. On the other hand, San Miguel showed only a positive correlation between α-tocopherol level and VTE1gene expression.

Liposoluble vitamins A and E in kidney disease

Kidney disease (KD) is characterized by the presence of elevated oxidative stress, and this is postulated as contributing to the high cardiovascular morbidity and mortality in these individuals. Chronic KD (CKD) is related to high grade inflammatory condition and pro-oxidative state that aggravates the progression of the disease by damaging primary podocytes. Liposoluble vitamins (vitamin A and E) are potent dietary antioxidants that have also anti-inflammatory and antiapoptotic functions. Vitamin deficits in CKD patients are a common issue, and multiple causes are related to them: Anorexia, dietary restrictions, food cooking methods, dialysis losses, gastrointestinal malabsorption, etc. The potential benefit of retinoic acid (RA) and α-tocopherol have been described in animal models and in some human clinical trials. This review provides an overview of RA and α tocopherol in KD.

Deuterated polyunsaturated fatty acids inhibit photoirradiation-induced lipid peroxidation in lipid bilayers

Lipid peroxidation (LPO) plays a key role in many age-related neurodegenerative conditions and other disorders. Light irradiation can initiate LPO through various mechanisms and is of importance in retinal and dermatological pathologies. The introduction of deuterated polyunsaturated fatty acids (D-PUFA) into membrane lipids is a promising approach for protection against LPO. Here, we report the protective effects of D-PUFA against the photodynamically induced LPO, using illumination in the presence of the photosensitizer trisulfonated aluminum phthalocyanine (AlPcS₃) in liposomes and giant unilamellar vesicles (GUV), as assessed in four experimental models: 1) sulforhodamine B leakage from liposomes, detected with fluorescence correlation spectroscopy (FCS); 2) formation of diene conjugates in liposomal membranes, measured by absorbance at 234 nm; 3) membrane leakage in GUV assessed by optical phase-contrast intensity observations; 4) UPLC-MS/MS method to detect oxidized linoleic acid (Lin)-derived metabolites. Specifically, in liposomes or GUV containing H-PUFA (dilinoleyl-sn-glycero-3-phosphatidylcholine), light irradiation led to an extensive oxidative damage to bilayers. By contrast, no damage was observed in lipid bilayers containing 20% or more D-PUFA (D2-Lin or D10-docosahexanenoic acid). Remarkably, addition of tocopherol increased the dye leakage from liposomes in H-PUFA bilayers compared to photoirradiation alone, signifying tocopherol's pro-oxidant properties. However, in the presence of D-PUFA the opposite effect was observed, whereby adding tocopherol increased the resistance to LPO. These findings suggest a method to augment the protective effects of D-PUFA, which are currently undergoing clinical trials in several neurological and retinal diseases that involve LPO.

Asthma, allergy and vitamin E: Current and future perspectives

Asthma and allergic disease result from interactions of environmental exposures and genetics. Vitamin E is one environmental factor that can modify development of allergy early in life and modify responses to allergen after allergen sensitization. Seemingly varied outcomes from vitamin E are consistent with the differential functions of the isoforms of vitamin E. Mechanistic studies demonstrate that the vitamin E isoforms α-tocopherol and γ-tocopherol have opposite functions in regulation of allergic inflammation and development of allergic disease, with α-tocopherol having anti-inflammatory functions and γ-tocopherol having pro-inflammatory functions in allergy and asthma. Moreover, global differences in prevalence of asthma by country may be a result, at least in part, of differences in consumption of these two isoforms of tocopherols. It is critical in clinical and animal studies that measurements of the isoforms of tocopherols be determined in vehicles for the treatments, and in the plasma and/or tissues before and after intervention. As allergic inflammation is modifiable by tocopherol isoforms, differential regulation by tocopherol isoforms provide a foundation for development of interventions to improve lung function in disease and raise the possibility of early life dietary interventions to limit the development of lung disease.

Vitamin E: How much is enough, too much and why!

α-Tocopherol (α-T) is a required dietary nutrient for humans and thus is a vitamin. This narrative review focuses on vitamin E structures, functions, biological determinants and its deficiency symptoms in humans. The mechanisms for the preferential α-T tissue enrichment in the human body include the α-T transfer protein (TTPA) and the preferential metabolism of non-α-T forms. Potential new α-T biomarkers, pharmacokinetic data, and whether there are better approaches to evaluate and set the α-T dietary requirement are discussed. Finally, the possible role of α-T supplements in delay of chronic diseases and the evaluation of vitamin E safety are considered.

α-Tocopherol transfer protein (α-TTP)

α-Tocopherol transfer protein (α-TTP) is so far the only known protein that specifically recognizes α-tocopherol (α-Toc), the most abundant and most biologically active form of vitamin E, in higher animals. α-TTP is highly expressed in the liver where α-TTP selects α-Toc among vitamin E forms taken up via plasma lipoproteins and promotes its secretion to circulating lipoproteins. Thus, α-TTP is a major determinant of plasma α-Toc concentrations. Familial vitamin E deficiency, also called Ataxia with vitamin E deficiency, is caused by mutations in the α-TTP gene. More than 20 different mutations have been found in the α-TTP gene worldwide, among which some missense mutations provided valuable clues to elucidate the molecular mechanisms underlying intracellular α-Toc transport. In hepatocytes, α-TTP catalyzes the vectorial transport of α-Toc from the endocytotic compartment to the plasma membrane (PM) by targeting phosphatidylinositol phosphates (PIPs) such as PI(4,5)P₂. By binding PIPs at the PM, α-TTP opens the lid covering the hydrophobic pocket, thus facilitating the release of bound α-Toc to the PM.

Pre-analytical monitoring and protection of oxidizable lipids in human plasma (vitamin E and ω-3 and ω-6 fatty acids): An update for redox-lipidomics methods

Sample manipulation for storage and storage itself, interfere with the stability of labile lipids in human plasma, including vitamin E (α-tocopherol), polyunsaturated fatty acids (PUFAs), and their enzymatic and free radical-derived oxidation metabolites. This remains a main limit of lipidomics studies that often lack of sufficient standardization and validation at the pre-analytical level. In order to characterize the stability of these lipids in human plasma and to develop a standardized pre-analytical protocol for lipidomics methods, the oxidation metabolites of α-tocopherol, the free form of ω3 and ω6 PUFAs, and some arachidonic acid (AA)-derived eicosanoids were investigated in human plasma during storage at different freezing temperatures. The effect of a protection/defense cocktail of antioxidants and lipoxygenase inhibitors (PD solution) on these lipid parameters was also evaluated. The temperature of storage markedly affected the formation of α-tocopheryl quinone (α-TQ), the main lipoperoxyl radical-derived oxidation metabolite of vitamin E, with the lowest production rate observed in samples stored at -80 °C or in liquid nitrogen. A similar effect of the storage temperature was observed for the free form of the ω-3 species eicosapentaenoic and docosahexaenoic acid, and for the ω-6 AA. Freezing samples at -20 °C resulted in a time-dependent formation of the pro-inflammatory eicosanoid LTB4. The PD solution prevents non-specific alterations of these lipid parameters in samples that are processed for direct analysis and protects from the temperature-dependent modifications of free PUFAs. Combining PD solution and preservation at -80 °C or in liquid nitrogen, resulted in levels of α-TQ and PUFAs that remained stable over 1 month and up to 8 months of storage, respectively. This method paper provides indications for the optimal processing and storage of human plasma utilized in lipidomics studies.

Involvement of PD-L1-mediated Tumor Intrinsic Signaling and Immune Suppression in Tumorigenic Effect of α-Tocopherol

Numerous studies have shown that the different isoforms vitamin E have distinct activity on carcinogenesis. α-Tocopherol (α-T), the most abundant vitamin E in certain types of food and animal tissues, has demonstrated a cancer-promoting effect in a number of human clinical trials and pre-clinical studies, whereas the γ- and δ- forms of Tocopherols and Tocotrienols have exhibited significant anticancer effect in various pre-clinical studies. However, the mechanisms underlying the tumorigenic effect of α-T have not yet been fully understood. In the present study, we found that α-T was able to activate Programmed death-ligand 1 (PD-L1)-mediated tumor-intrinsic signaling and immune suppression via JAK/STAT3-dependent transcriptional and ERK-dependent posttranscriptional mechanism. In line with PD-L1 induction, α-T treatment increased cancer cell viability in vitro and promoted tumor growth in LLC xenograft mouse model. The findings of the present study for the first time provided evidence that PD-L1-mediated tumor-intrinsic and immune escape mechanism contributed to the tumorigenic effect of α-T.

The chemoprotective effects of IFN-α-2b on rat hepatocarcinogenesis are blocked by vitamin E supplementation

Many cancer patients receive their classical therapies together with vitamin supplements. However, the effectiveness of these strategies is on debate. Here we aimed to evaluate how vitamin E supplementation affects the anticancer effects of interferon (IFN-α) using an early-model of liver cancer development (initiation-promotion, IP). Male Wistar rats subjected to this model were divided as follows: untreated (IP), IP treated with recombinant IFN-α-2b (6.5  ×  105 U/kg), IP treated with vitamin E (50 mg/kg), and IP treated with combination of vitamin E and IFN-α-2b. After treatments rats were fasted and euthanized and plasma and livers were collected. Combined administration of vitamin E and IFN-α-2b induced body weight drop, increased liver apoptosis, and low levels of hepatic lipids. Interestingly, vitamin E and IFN-α-2b combination also induced an increase in altered hepatic foci number, but not in size. It seems that vitamin E acts on its antioxidant capability in order to block the oxidative stress induced by IFN-α-2b, blocking in turn its beneficial effects on preneoplastic livers, leading to harmful final effects. In conclusion, this study shows that vitamin E supplementation in IFN-α-2b-treated rats exerts unwanted effects; and highlights that in spite of being natural, nutritional supplements may not always exert beneficial outcomes when used as complementary therapy for the treatment of cancer.

Investigation of electrical properties of eco-friendly vegetable oil blended with bioactive compound

Oxidative stability of prototypical groundnut oil (GO) and mustard oil (MO) blended with a significant characteristic addition of antioxidants, α-tocopherol (α-T) and TBHQ (tert-butyl hydroquinone), at different concentrations was analysed. α-T (natural) and TBHQ (synthetic) antioxidants at a different concentrations from 0 to 20 mg/L were blended with GO and MO to prepare 18 samples. Compositional analysis of groundnut oil and mustard oil was carried out using gas chromatography and mass spectra (GCMS). Electrical properties like dielectric constant, tanδ, specific resistance etc. were investigated at frequencies from 1 Hz to 10 MHz for the modified samples. Thermal properties like breakdown voltage, flash and fire points and viscosity of all samples were also premeditated. It was observed that dielectric constant (ε') of GO reduces from 3.58 to 2.82 with the addition of α-T but increases to 3.29 with the addition of TBHQ, whereas in MO, dielectric constant increases from 2.93 to 3.38 with the addition of α-T and rises to 3.27 with the addition of TBHQ at 15 mg/L. The synergistic effect of antioxidants in regulating the insulation nature of the oil is found to be more effective with α-tocopherol compared to TBHQ in GO. Higher breakdown voltage and more stability were observed in oil with the addition of antioxidant (TBHQ) in low concentration. The study would be useful in the selection of eco-friendly coolants in engineering and industry.

Evaluation of total phenols content, anti-DPPH activity and the content of selected antioxidants in the honeybee drone brood homogenate

The subject of the present research is the evaluation of health-promoting properties caused by the presence of some vitamins as well as the antioxidative potential of the honeybee drone brood homogenate (DBH). The study used 139 homogenate samples obtained from various apiaries and collected over 3 years, three times during each beekeeping season. Samples differed in terms of varroa infestation, stage of brood development, location of the apiary, and the degree of environmental contamination. The content of ascorbic acid, α-tocopherol, all-trans-retinol, and coenzyme Q₁₀ in the tested samples was determined through the application of HPLC/DAD/UV and LC/QQQ/MS methods. The antioxidant potential of samples was assessed using the Folin-Ciocalteu and DPPH methods.

The genotoxic effects of perchloroethylene in human peripheral blood lymphocytes and the possible ameliorative role of α-tocopherol

Perchloroethylene (PCE), also known as tetrachloroethylene, is a commercially important chlorinated solvent commonly used in dry cleaning, textile processing, and metal degreasing industries. According to the available studies, the potential genotoxic impacts of this chlorinated solvent on human beings are still controversial. The present work was carried out to determine the genotoxic effects of PCE on human peripheral blood lymphocytes (PBLs) using chromosome aberrations (CAs) and cytokinesis-block micronucleus (CBMN) tests. Additionally, the antigenotoxic potential of α-tocopherol (α-Toc), a well-known antioxidant agent, on human lymphocytes treated with PCE in vitro was assessed. The cells were exposed for 48 h to PCE (25, 50, 100, and 150 μg/mL) alone as well as in combination with α-Toc (100 μg/mL). The findings of the study suggested that, relative to solvent control, PCE significantly increased the structural CA and MN formation for all concentrations. However, simultaneous treatment of PCE and α-Toc caused a significant reduction of CAs and MNi as compared to cultures treated with PCE alone. Besides, the results showed that PCE has cytotoxic effects on human PBLs as indicated by the significant decrease in mitotic index (MI) and nuclear division index (NDI). Nevertheless, the co-treatment of α-Toc with PCE did not reduce the cytotoxicity of PCE at a significant level. In conclusion, it can be suggested that PCE is genotoxic and cytotoxic in human PBLs, and α-Toc has an antigenotoxic effect on PCE-induced genotoxicity but has no significant effect on the cytotoxicity triggered by PCE.

Alpha-Tocopherol Protects Human Dermal Fibroblasts by Modulating Nitric Oxide Release, Mitochondrial Function, Redox Status, and Inflammation

BACKGROUND

The altered balance between oxidants/antioxidants and inflammation, changes in nitric oxide (NO) release, and mitochondrial function have a role in skin aging through fibroblast modulation. Tocopherol is promising in counteracting the abovementioned events, but the effective mechanism of action needs to be clarified.

OBJECTIVE

The aim of this study was to examine the effects of α-tocopherol on cell viability/proliferation, NO release, mitochondrial function, oxidants/antioxidants, and inflammation in human dermal fibroblasts (HDF) subjected to oxidative stress.

METHODS

HDF were treated with H2O2 in the presence or absence of 1-10 μM α-tocopherol. Cell viability, reactive oxygen species (ROS), NO release, and mitochondrial membrane potential were measured; glutathione (GSH), superoxide dismutase (SOD)-1 and -2, glutathione peroxidase-1 (GPX-1), inducible NO synthase (iNOS), and Ki-67 were evaluated by RT-PCR and immunofluorescence; cell cycle was analyzed using FACS. Pro- and anti-inflammatory cytokine gene expression was analyzed through qRT-PCR.

RESULTS

α-Tocopherol counteracts H2O2, although it remains unclear whether this effect is dose dependent. Improvement of cell viability, mitochondrial membrane potential, Ki-67 expression, and G0/G1 and G2/M phases of the cell cycle was observed. These effects were accompanied by the increase of GSH content and the reduction of SOD-1 and -2, GPX-1, and ROS release. Also, iNOS expression and NO release were inhibited, and pro-inflammatory cytokine gene expression was decreased, confirming the putative role of α-tocopherol against inflammation.

CONCLUSION

α-Tocopherol exerts protective effects in HDF which underwent oxidative stress by modulating the redox status, inflammation, iNOS-dependent NO release, and mitochondrial function. These observations have a potential role in the prevention and treatment of photoaging-related skin cancers.

Systematic review and meta-analyses of vitamin E (alpha-tocopherol) supplementation and blood lipid parameters in patients with diabetes mellitus

BACKGROUND AND AIMS

The studies have shown that α-tocopherol supplementation could improve lipid profile in diabetes mellitus (DM) patients. Nonetheless, the result remains inconsistent. Therefore, this meta-analysis was performed to evaluate the efficacy of α-tocopherol supplement on lipid parameters in DM patients.

METHODS

We conducted an extensive search via Cochrane Library, PubMed, Scopus, and Web of Science databases to acquire the reported RCTs up to October 2020.

RESULTS

The results showed no effects of α-tocopherol supplementation on lipid profile in DM patients except when used ≥12 weeks.

CONCLUSIONS

α-tocopherol supplementation in DM patients had no significant effect on lipid profiles.

Alpha2-Adrenoblockers Regulate Development of Oxidative Stress and Cognitive Behaviour of Rats under Chronic Acoustic Stress Conditions

Noise is a wide-spread stress factor in modern life produced by urbanization, traffic, and an industrialized environment. Noise stress causes dysfunction and neurotransmission impairment in the central nervous system, as well as changes in hormone levels. In this study, we have examined the level of α-Tocopherol (α-T) and malondialdehyde (MDA) in plasma and the erythrocytes’ membrane (EM), as well as the behavioral characteristics of a noise-induced stress model in rats. In addition, the modulating effect of α²-adrenoblockers, beditin, and mesedin on the aforementioned parameters has been investigated. For these purposes, albino male rats were divided into four groups: (1) untreated; (2) noise-exposed, (3) noise-exposed and beditin-treated (2 mg/kg, i.p.), and (4) noise-exposed and mesedin-treated (10 mg/kg, i.p.) animals. Noise-exposed groups were treated with 91dBA noise on 60 days with a daily duration of 8 h. Increased MDA and decreased α-T levels in plasma and EM were observed upon chronic high-level noise exposure. Locomotor and behavioral activity assessed with a Y-maze revealed disorientation and increased anxiety under chronic noise exposure. Prominently, α²-adrenoblockers alleviated both behavioral deficits and oxidative stress, providing evidence for the involvement of α²-adrenoceptor in the pathophysiology of noise-induced stress.

Vitamin E: necessary nutrient for neural development and cognitive function

Vitamin E, discovered in 1922, is essential for pregnant rats to carry their babies to term. However, 100 years later, the molecular mechanisms for the vitamin E requirement during embryogenesis remain unknown. Vitamin E's role during pregnancy has been difficult to study and thus, a vitamin E-deficient (E-) zebrafish embryo model was developed. Vitamin E deficiency in zebrafish embryos initiates lipid peroxidation, depletes a specific phospholipid (DHA-phosphatidyl choline), causes secondary deficiencies of choline, betaine and critical thiols (such as glutathione), and dysregulates energy metabolism. Vitamin E deficiency not only distorts the carefully programmed development of the nervous system, but it leads to defects in several developing organs. Both the α-tocopherol transfer protein and vitamin E are necessary for embryonic development, neurogenesis and cognition in this model and likely in human embryos. Elucidation of the control mechanisms for the cellular and metabolic pathways involved in the molecular dysregulation caused by vitamin E deficiency will lead to important insights into abnormal neurogenesis and embryonic malformations.

Interactions between α-tocopherol and γ-oryzanol in oil-in-water emulsions

The interaction between antioxidants is affected by many factors, such as concentration, ratio and system. In this study, different concentrations of α-tocopherol and γ-oryzanol showed antagonistic effect in the oil-in-water emulsion, and the distribution of α-tocopherol increased in aqueous phase after combined with γ-oryzanol. The concentration could affect the degree of antagonism. According to fluorescence quenching, cyclic voltammetry measurements and the oxidative decomposition of antioxidants during storage, the inhibitory effect of γ-oryzanol on the regeneration of α-tocopherol was proposed to be responsible for the antagonism. This work can provide suggestions for studying the mechanism of antioxidant interaction in emulsion system.

Rutin, α-tocopherol, and l-ascorbic acid up-regulate type I interferon-regulated gene and type I and II interferon expressions and reduce inflammatory cytokine expressions in monocyte-derived macrophages infected with highly pathogenic porcine reproductive and respiratory syndrome virus

This study evaluated the immunomodulatory effect of two types of phytochemicals, i.e. rutin and β-carotene, and two types of vitamins, i.e. α-tocopherol and l-ascorbic acid on improving innate immune responses to highly pathogenic porcine reproductive and respiratory syndrome virus (HP-PRRSV). Monocyte-derived macrophages (MDM) from eight PRRSV-seronegative pigs were inoculated with HP-PRRSV and subsequently stimulated with rutin, β-carotene, α-tocopherol, and l-ascorbic acid in the absence or presence of either polyinosinic:polycytidylic acid or lipopolysaccharide. The mRNA expression levels of myxovirus resistance 1, interferon regulatory factor 3 (IRF3), IRF7, 2'-5'-oligoadenylatesynthetase 1, stimulator of interferon genes (STING), osteopontin (OPN), interferon alpha (IFNα), IFNβ, IFNγ, interleukin-10 (IL-10), tumor necrosis factor alpha (TNFα), and transforming growth factor beta (TGFβ) were evaluated by real-time PCR. Compared with control MDM, HP-PRRSV significantly suppressed mRNA expressions of all immune-related genes except IL-10 and TGFβ. Compared with HP-PRRSV-inoculated MDM, stimulation with rutin, α-tocopherol, and l-ascorbic acid, but not β-carotene significantly enhanced mRNA expression levels of IRF3, IRF7, STING, OPN, IFNα, IFNβ, and IFNγ in HP-PRRSV-inoculated MDM. Stimulation with rutin also significantly reduced mRNA expression levels of TNFα and TGFβ, whereas stimulation with β-carotene and α-tocopherol significantly reduced TNFα mRNA expression in HP-PRRSV-inoculated MDM. Our findings demonstrate the potentials of rutin, α-tocopherol, and l-ascorbic acid in enhancing type I interferon-regulated genes and type I and II IFN expressions, and in reducing pro- and/or anti-inflammatory cytokine expressions in HP-PRRSV-inoculated MDM. Our findings suggest that rutin, α-tocopherol, and l-ascorbic acid may serve as effective immunomodulators for improving innate immune response to HP-PRRSV.

Oral delivery of all-trans retinoic acid mediated by liposome carriers

All-trans retinoic acid (ATRA) is a molecule that finds wide applications in medicine. Connection between cancer cell proliferation and ATRA is a well-established item. Driven by the potential applications of liposomes in stabilizing and protecting therapeutic compounds thus enabling effective delivery of encapsulated compounds, recent research efforts have been directed to understanding mechanisms of oral delivery through the gastrointestinal tract. The surface charge of the liposome bilayers can modify the interactions between the aggregates and the gastrointestinal fluids. Here, we investigated the ability of cationic and anionic liposomes to encapsulate, protect and deliver ATRA in an in-vitro digestion process as a different oral administration route. Stability and encapsulation efficiency of ATRA in negatively and positively charged liposomes enriched with α-tocopherol were investigated by means of UV-vis spectroscopy, dynamic light scattering and ζ-potential. The applicability of the carriers was tested by means of an in-vitro digestion procedure allowing for the measurement of the bioavailability of ATRA. From this study evidence was provided that the water insoluble molecules, ATRA and α-tocopherol are intercalated in liposome membranes regardless of the surface charge of the vesicle bilayers. Comparisons between cationic and anionic liposomes incorporating retinoic acid show differences in bioavailability. The cationic vesicles are preferable for a larger amount of ATRA bioavailability, which can be understood from electrostatic interactions. Thus ATRA is ionized in a wide range of pHs but protonated in anionic vesicles.

Food additive-induced oxidative stress in rat male reproductive organs and hippocampus

As currently defined, the exposome represents the lifetime exposure measure of an individual to all potential external genetic influences and their impact on health. Although intentionally added chemicals (e.g., food additives) and food contact materials (e.g., packaging, pesticides) have been assessed for safety to some degree, the full extent to which they can affect health and reproduction has not been reported. The aim of this study was to determine the in vitro and in vivo effects of food additives on the male rat brain and sperm/testes, particularly through oxidative stress. Results from our in vitro study demonstrated that the administration of the common food additive, stevioside, a major component of the common sweetener stevia, as well as the preservatives, diphenyl and orthophenyl phenol (OPP), induced reactive oxygen species (ROS) production in sperm, and led to sperm dysfunction. These effects were inhibited by the addition of the antioxidant α-tocopherol. Moreover, OPP treatment (1/10,000 of no observed adverse effect) induced ROS production in sperm and lipid peroxidation in the epididymis and hippocampus after two weeks in vivo. Furthermore, 4-hydroxynonenal-positive cells, indicating ROS-generated protein modifications, were detected in spermatocytes in the testes and granular cell layer of the dentate gyrus in the brain. Treatment with α-tocopherol significantly improved oxidative stress. Our study suggests that certain food additives may affect sperm function and induce oxidative stress in the testes and brain, resulting in infertility and short-term memory loss, and some antioxidants may improve these dysfunctions.

Serum vitamin E level and gestational diabetes mellitus: a systematic review and meta-analysis

Purpose

Gestational diabetes mellitus (GDM) is one of the most common medical complications in pregnancy. This systematic review aimed to evaluate the association between vitamin E and GDM.

Methods

Relevant articles from the Cochrane Library, PubMed, Scopus, Science Direct, Web of Science, and EMBASE databases up to December 2019 were searched. The inclusion criteria were observational full-text articles. The fixed and random effect models were used to analyze the pooled data using Review Manager 5.3.

Results

Thirteen studies, including 596 participants, of whom 285 were diagnosed with GDM were included in the meta-analysis. The vitamin E level was significantly lower in women with GDM (MD: - 0.10; 95% CI: [-0.15, - 0.05]). The level of vitamin E was not different between overweight women with GDM and healthy pregnant women (MD: 0.03; 95% CI: [-0.08, 0.013]). The level of vitamin E was significantly lower in the third trimester of pregnancy in GDM women in comparison to the healthy pregnant women(MD: -0.09; 95% CI: [-0.12, -0.06]).

Conclusion

This study showed that the level of vitamin E is significantly lower in GDM women compared to healthy pregnant women.

Advancing skin delivery of α-tocopherol and γ-tocotrienol for dermatitis treatment via nanotechnology and microwave technology

This study investigated combination nanocarrier and microwave system for α-tocopherol and γ-tocotrienol delivery against dermatitis, without skin thinning effect of steroids. The vitamin E was formulated into water-rich/water-poor nanoemulsions, and had their droplet size, zeta potential, morphology, therapeutic content, encapsulation efficiency and release, in vitro skin therapeutics/nanoemulsion penetration, retention and permeation profiles, and in vivo pharmacodynamics characteristics examined, with skin pre-treated by precision microwave when applicable. The nanoemulsions had droplet sizes <150 nm and negative zeta potential values. The skin pre-treatment by microwave (1 mW/3985 MHz) promoted therapeutics accumulation in epidermis through enhancing nanoemulsion penetration into skin. The combination nano- and microwave technologies fluidized skin lipid and protein domains with epidermal microstructures being fluidized to a greater extent than dermis, allowing a relatively high epidermal-to-dermal nanoemulsion distribution. Microwave of lower or higher than 3985 MHz brought about lower skin therapeutics/nanoemulsion accumulation due to insufficient lipid/protein domain fluidization or microwave-skin interaction limiting at skin surfaces only. Using water-rich nanoemulsion with higher therapeutic release and skin pre-treatment with 3985 MHz microwave, dermatitis was alleviated in vivo without skin thinning of standard steroid. The use of combination microwave and nanotechnology promotes vitamin delivery and translates to positive dermatitis treatment outcome that warrants future investigation.

Linking jasmonates with vitamin E accumulation in plants: a case study in the Mediterranean shrub Cistus albidus L

Jasmonic acid positively modulates vitamin E accumulation, but the latter can also partly influence the capacity to accumulate the jasmonic acid precursor, 12-oxo-phytodienoic acid, in white-leaved rockrose (Cistus albidus L.) plants growing in their natural habitat. This study suggests a bidirectional link between chloroplastic antioxidants and lipid peroxidation-derived hormones in plants. While vitamin E is well known for its antioxidant properties being involved in plant responses to abiotic stress, jasmonates are generally related to biotic stress responses in plants. Studying them in non-model plants under natural conditions is crucial for the knowledge on their relationship, which will help us to better understand mechanisms and limits of stress tolerance to implement better conservation strategies in vulnerable ecosystems. We studied a typical Mediterranean shrub, white-leaved rockrose (Cistus albidus) under natural conditions during three winters and we analyzed both α and γ-tocopherol, and the three main jasmonates forms 12-oxo-phytodienoic acid (OPDA), jasmonic acid (JA), and jasmonoyl-isoleucine (JA-Ile). We found that JA contents positively correlated with vitamin E accumulation, most particularly with γ-tocopherol, the precursor of α-tocopherol (the most active vitamin E form). This finding was confirmed by exogenous application of methyl jasmonate (MeJA) in leaf discs under controlled conditions, which increased γ-tocopherol when applied at 0.1 mM MeJA and α-tocopherol at 1 mM MeJA. Furthermore, a complementary meta-analysis study with previously published reports revealed a positive correlation between JA and vitamin E, although this relationship turned to be strongly species specific. A strong negative correlation was observed, however, between total tocopherols and OPDA (a JA precursor located in chloroplasts). This antagonistic effect was observed between α-tocopherol and OPDA, but not between γ-tocopherol and OPDA. It is concluded that (i) variations in jasmonates and vitamin E due to yearly, inter-individual and sun orientation-driven variability are compatible with a partial regulation of vitamin E accumulation by jasmonates, (ii) vitamin E may also exert a role in the modulation of the biosynthesis of OPDA, with a much smaller effect, if any, on other jasmonates, and (iii) a trade-off in the accumulation of vitamin E and jasmonates might occur in the regulation of biotic and abiotic stress responses in plants.

The vitamin E long-chain metabolite α-13'-COOH affects macrophage foam cell formation via modulation of the lipoprotein lipase system

The α-tocopherol-derived long-chain metabolite (α-LCM) α-13'-carboxychromanol (α-13'-COOH) is formed via enzymatic degradation of α-tocopherol (α-TOH) in the liver. In the last decade, α-13'-COOH has emerged as a new regulatory metabolite revealing more potent or even different effects compared with its vitamin precursor α-TOH. The detection of α-13'-COOH in human serum has further strengthened the concept of its physiological relevance as a potential regulatory molecule. Here, we present a new facet on the interaction of α-13'-COOH with macrophage foam cell formation. We found that α-13'-COOH (5 μM) increases angiopoietin-like 4 (ANGPTL4) mRNA expression in human THP-1 macrophages in a time- and dose-dependent manner, while α-TOH (100 μM) showed no effects. Interestingly, the mRNA level of lipoprotein lipase (LPL) was not influenced by α-13'-COOH, but α-TOH treatment led to a reduction of LPL mRNA expression. Both compounds also revealed different effects on protein level: while α-13'-COOH reduced the secreted amount of LPL protein via induction of ANGPTL4 cleavage, i.e. activation, the secreted amount of LPL in the α-TOH-treated samples was diminished due to the inhibition of mRNA expression. In line with this, both compounds reduced the catalytic activity of LPL. However, α-13'-COOH but not α-TOH attenuated VLDL-induced lipid accumulation by 35%. In conclusion, only α-13'-COOH revealed possible antiatherogenic effects due to the reduction of VLDL-induced foam cell formation in THP-1 macrophages. Our results provide further evidence for the role of α-13'-COOH as a functional metabolite of its vitamin E precursor.

Effect of steam sterilisation on lipophilic nutrient stability in a chloroplast-rich fraction (CRF) recovered from postharvest, pea vine field residue (haulm)

Postharvest, pea vine field residue (haulm) was steam-sterilised and then juiced; a chloroplast-rich fraction (CRF) was recovered from the juice by centrifugation. The stability of selected nutrients (β-carotene, lutein, and α-tocopherol) in the freeze-dried CRF material was measured over 84 days; the impact of temperature (-20 °C, 4 °C, 25 °C and 40 °C), light and air on nutrient stability was established. All three nutrients were stable at -20 °C and 4 °C in the presence or absence of air; this stability was lost at higher temperatures in the presence of air. The extent and rate of nutrient breakdown significantly increased when the CRF samples were exposed to light. β-Carotene appeared to be more susceptible to degradation than lutein and α-tocopherol at 40 °C in the presence of air, but when CRF was exposed to light all three nutrients measured were significantly broken down during storage at 25 °C or 40 °C, whether exposed to air or not.

Vitamin E status among bariatric surgery patients: a systematic review

Vitamin E, a fat-soluble vitamin with antioxidant properties, is thought to modulate enzymes involved in signal transduction, affect gene expression, and have immunomodulatory capabilities. Severe vitamin E deficiency is associated with neuronal disorders, impaired immune response, hemolytic anemia, and oxidative-based disorders. Patients who undergo bariatric surgery (BS), especially malabsorptive procedures, are at greater risk of developing fat-soluble vitamin deficiencies. Current data on vitamin E statuses among BS patients are limited. Therefore, this systematic review has summarized the scientific literature on vitamin E and examined its status among patients following different types of BS. Searches of the MEDLINE and Embase databases were performed, followed by hand-searching of reference lists from all relevant papers. Of the 671 initially identified articles, 24 met the inclusion criteria: 1 study on adjustable gastric banding patients (n = 21), 4 studies on sleeve gastrectomy patients (n = 173), 12 studies on Roux-en-Y gastric bypass patients (n = 689) and 12 studies on biliopancreatic diversion with or without duodenal switch (n = 799) or single anastomosis duodeno-ileal bypass with sleeve gastrectomy patients (n = 163). Results suggest that patients who undergo malabsorptive procedures are at higher risk of developing vitamin E deficiency, although clinical manifestations of vitamin E deficits following BS are rarely documented. The optimal dose of vitamin E supplementation required for prevention of deficiency or for treatment following BS has yet to be established. Future observational and intervention studies are needed to bridge the gaps in existing knowledge.

Doxyl Nitroxide Spin Probes Can Modify Toxicity of Doxorubicin towards Fibroblast Cells

The biological properties of doxyl stearate nitroxides (DSs): 5-DS, Met-12-DS, and 16-DS, commonly used as spin probes, have not been explored in much detail so far. Furthermore, the influence of DSs on the cellular changes induced by the anticancer drug doxorubicin (DOX) has not yet been investigated. Therefore, we examined the cytotoxicity of DSs and their ability to induce cell death and to influence on fluidity and lipid peroxidation (LPO) in the plasma membrane of immortalised B14 fibroblasts, used as a model neoplastic cells, susceptible to DOX-induced changes. The influence of DSs on DOX toxicity was also investigated and compared with that of a natural reference antioxidant α-Tocopherol. By employing the trypan blue exclusion test and double fluorescent staining, we found a significant level of cytotoxicity for DSs and showed that their ability to induce apoptosis and modify plasma membrane fluidity (measured fluorimetrically) is more potent than for α-Tocopherol. The most cytotoxic nitroxide was 5-DS. The electron paramagnetic resonance (EPR) measurements revealed that 5-DS was reduced in B14 cells at the fastest and Met-12-DS at the slowest rate. In the presence of DOX, DSs were reduced slower than alone. The investigated compounds, administered with DOX, enhanced DOX-induced cell death and demonstrated concentration-dependent biphasic influence on membrane fluidity. A-Tocopherol showed weaker effects than DSs, regardless the mode of its application—alone or with DOX. High concentrations of α-Tocopherol and DSs decreased DOX-induced LPO. Substantial cytotoxicity of the DSs suggests that they should be used more carefully in the investigations performed on sensitive cells. Enhancement of DOX toxicity by DSs showed their potential to act as chemosensitizers of cancer cells to anthracycline chemotherapy.

Synergic antioxidant activity of γ-terpinene with phenols and polyphenols enabled by hydroperoxyl radicals

Antioxidant interactions of γ-terpinene with α-tocopherol mimic 2,2,5,7,8-pentamethyl-6-chromanol (PMHC) and caffeic acid phenethyl ester (CAPE), used as models, respectively, of mono- and poly-phenols were demonstrated by differential oximetry during the inhibited autoxidation of model substrates: stripped sunflower oil, squalene, and styrene. With all substrates, γ-terpinene acts synergistically regenerating the chain-breaking antioxidants PMHC and CAPE from their radicals, via the formation of hydroperoxyl radicals. The inhibition duration for mixtures PMHC/γ-terpinene and CAPE/γ-terpinene increased with γ-terpinene concentration, while rate constants for radical-trapping were unchanged by γ-terpinene, being 3.1 × 10⁶ and 4.8 × 10⁵ M^-1s^-1 for PMHC and CAPE in chlorobenzene (30 °C). Using 3,5-di-tert-butylcatechol and 3,5-di-tert-butyl-1,2-bezoquinone we demonstrate that γ-terpinene can reduce quinones to catechols enabling their antioxidant activity. The different synergy mechanism of γ-terpinene with mono- and poly-phenolic antioxidants is discussed and its relevance is proven in homogenous lipids using natural α-tocopherol and hydroxytyrosol as antioxidants, calling for further studies in heterogenous food products.

Differential accumulation of tocochromanols in photosynthetic and non-photosynthetic tissues of strawberry plants subjected to reiterated water deficit

Tocochromanols are a group of lipid-soluble antioxidants that include tocopherols, tocotrienols and plastochromanol-8. Here, we examined a putative differential accumulation of tocochromanols in photosynthetic and non-photosynthetic tissues (including leaves and whole fruits) of strawberry (Fragaria x ananassa cv. Albion) plants and evaluated their endogenous variations in response to a reiterated water deficit during a vegetative (non-productive) and a fruiting (productive) period. In addition, we evaluated the concentration of tocochromanols in achenes (true fruits) and flesh of strawberries (whole fruits) at the white and full-red stages both under optimal and stress conditions. Results showed that leaves mainly accumulated α-tocopherol, with plastochromanol-8 and γ-tocopherol being present at low amounts. In contrast, whole fruits did not accumulate plastochromanol-8, γ-tocopherol being the major tocochromanol in the achenes (true fruit) and α-tocopherol in the flesh. While α-tocopherol content in leaves increased up to seven-fold after 12 weeks of stress during the fruiting period, it kept unaltered during the vegetative period. Neither plastochromanol-8 nor γ-tocopherol contents increased in leaves of stressed plants. During the fruiting period, γ-tocopherol content increased in whole fruits of stressed plants (most of it being accumulated in the achenes). Among the compounds examined, the flesh of strawberries accumulated α-tocopherol only, both at the white and full-red stages. It is concluded that (i) α-tocopherol is the major tocochromanol in leaves, while γ-tocopherol is the major tocochromanol in achenes (ii) reiterated water deficit promotes the accumulation of α-tocopherol in leaves and γ-tocopherol in fruits, (iii) α-tocopherol not only accumulates in photosynthetic tissues (leaves and whole fruits at green stages), but also in non-photosynthetic tissues (flesh of whole fruits at the white and full-red stages), and (iv) achenes (true fruits) of strawberry plants are an extraordinary rich source of tocopherols.

Systemic treatment with alpha-tocopherol and/or sodium selenite decreases the progression of experimental periodontitis

OBJECTIVE

To investigate the effects of sodium selenite (Se) and/or α-tocopherol (αT) applications on the alveolar bone loss (ABL), the number of gingival collagen fibers, inducible nitric oxide synthase (iNOS)+ and CD95+ cell numbers, and serum cytokine concentrations in experimental periodontitis in rats.

MATERIALS AND METHODS

Forty Sprague Dawley rats were divided into four groups of ten as follows: group A: Se group, group B: αT group, group C: Se and αT combined group, and group D: control group (intraperitoneal (IP) saline injection applied). Using the image analysis method in the connective tissue under the connective epithelium, the numbers of iNOS, CD95 positive cells, and collagen fibers were counted. ELISA kits were used to test the concentrations of serum interleukin (IL)-1β, IL-6, and IL-4.

RESULTS

The combination of Se and αT (group C) suppressed ABL compared with the control group (group D) (P < 0.05). In group A (Se), the number of iNOS+ cells was smaller than in group D (P < 0.05).

CONCLUSION

Se has been concluded to inhibit inflammation of the gum due to iNOS. Se and αT can have a remarkable important role in preventing alveolar bone loss, and particularly in combination.

CLINICAL RELEVANCE

Se and/or αT application may be useful in preventing the destruction of periodontal tissue and treatment of periodontal disease.

Effect of vitamin E on low density lipoprotein oxidation at lysosomal pH

Many cholesterol-laden foam cells in atherosclerotic lesions are macrophages and much of their cholesterol is present in their lysosomes and derived from low density lipoprotein (LDL). LDL oxidation has been proposed to be involved in the pathogenesis of atherosclerosis. We have shown previously that LDL can be oxidised in the lysosomes of macrophages. α-Tocopherol has been shown to inhibit LDL oxidation in vitro, but did not protect against cardiovascular disease in large clinical trials. We have therefore investigated the effect of α-tocopherol on LDL oxidation at lysosomal pH (about pH 4.5). LDL was enriched with α-tocopherol by incubating human plasma with α-tocopherol followed by LDL isolation by ultracentrifugation. The α-tocopherol content of LDL was increased from 14.4 ± 0.2 to 24.3 ± 0.3 nmol/mg protein. LDL oxidation was assessed by measuring the formation of conjugated dienes at 234 nm and oxidised lipids (cholesteryl linoleate hydroperoxide and 7-ketocholesterol) by HPLC. As expected, LDL enriched with α-tocopherol was oxidised more slowly than control LDL by Cu²⁺ at pH 7.4, but was not protected against oxidation by Cu²⁺ or Fe³⁺ or a low concentration of Fe²⁺ at pH 4.5 (it was sometimes oxidised faster by α-tocopherol with Cu²⁺ or Fe³⁺ at pH 4.5). α-Tocopherol-enriched LDL reduced Cu²⁺ and Fe³⁺ into the more pro-oxidant Cu⁺ and Fe²⁺ faster than did control LDL at pH 4.5. These findings might help to explain why the large clinical trials of α-tocopherol did not protect against cardiovascular disease.

Effects of α-tocopherol on hemolysis and oxidative stress markers on red blood cells in β-thalassemia major

BACKGROUND

The accumulation of unpaired α-globin chains in patients with β-thalassemia major may clinically create ineffective erythropoiesis, hemolysis, and chronic anemia. Multiple blood transfusions and iron overload cause cellular oxidative damage. However, α-tocopherol, an antioxidant, is a potent scavenger of lipid radicals in the membranes of red blood cells (RBCs) of patients with β-thalassemia major.

PURPOSE

To evaluate the effects of α-tocopherol on hemolysis and oxidative stress markers on the RBC membranes of patients with β-thalassemia major.

METHODS

Forty subjects included in this randomized controlled trial were allocated to the placebo and α-tocopherol groups. Doses of α-tocopherol were based on Institute of Medicine recommendations: 4-8 years old, 200 mg/day; 9-13 years old, 400 mg/day; 14-18 years old, 600 mg/day. Hemolysis, oxidative stress, and antioxidant variables were evaluated before and after 4-week α-tocopherol or placebo treatment, performed before blood transfusions.

RESULTS

Significant enhancements in plasma haptoglobin were noted in the α-tocopherol group (3.01 mg/dL; range, 0.60-42.42 mg/dL; P=0.021). However, there was no significant intergroup difference in osmotic fragility test results; hemopexin, malondialdehyde, reduced glutathione (GSH), or oxidized glutathione (GSSG) levels; or GSH/GSSG ratio.

CONCLUSION

Use of α-tocopherol could indirectly improve hemolysis and haptoglobin levels. However, it played no significant role in oxidative stress or as an endogen antioxidant marker in β-thalassemia major.

The effect of aging and antioxidants on photoreactivity and phototoxicity of human melanosomes: An in vitro study

Aging may significantly modify antioxidant and photoprotective properties of melanin in retinal pigment epithelium (RPE). Here, photoreactivity of melanosomes (MS), isolated from younger and older human donors with and without added zeaxanthin and α-tocopherol, was analyzed by electron paramagnetic resonance oximetry, time-resolved singlet oxygen phosphorescence, and protein oxidation assay. The phototoxic potential of ingested melanosomes was examined in ARPE-19 cells exposed to blue light. Phagocytosis of FITC-labeled photoreceptor outer segments (POS) isolated from bovine retinas was determined by flow cytometry. Irradiation of cells fed MS induced significant inhibition of the specific phagocytosis with the effect being stronger for melanosomes from older than from younger human cohorts, and enrichment of the melanosomes with antioxidants reduced the inhibitory effect. Cellular protein photooxidation was more pronounced in samples containing older melanosomes, and it was diminished by antioxidants. This study suggests that blue light irradiated RPE melanosomes could induce substantial inhibition of the key function of the cells-their specific phagocytosis. The data indicate that while photoreactivity of MS and their phototoxic potential increase with age, they could be reduced by selected natural antioxidants.

Hyaluronic-acid-based β-cyclodextrin grafted copolymers as biocompatible supramolecular hosts to enhance the water solubility of tocopherol

Hyaluronic acid (HA), a common biopolymer found in the extracellular fluid, was grafted with β-cyclodextrin (β-CD) to form a composite polymer that could form inclusion complexes with tocopherol (VE), enhancing its water-solubility and serving as a model drug delivery system. Herein, different copolymers were prepared with varying HA:β-CD ratios and characterized. VE loading capacity was directly correlated with increased β-CD composition in the polymers and morphological changes were observed upon VE binding. The host materials and their VE inclusion complexes are not cytotoxic, and are thus useful for VE and drug delivery.

Upregulation of pERK and c-JUN by γ-tocotrienol and not α-tocopherol are essential to the differential effect on apoptosis in prostate cancer cells

Background

α-tocopherol (AT) and γ-tocotrienol (GT3) are vitamin E isoforms considered to have potential chemopreventive properties. AT has been widely studied in vitro and in clinical trials with mixed results. The latest clinical study (SELECT trial) tested AT in prostate cancer patients, determined that AT provided no benefit, and could promote cancer. Conversely, GT3 has shown antineoplastic properties in several in vitro studies, with no clinical studies published to date. GT3 causes apoptosis via upregulation of the JNK pathway; however, inhibition results in a partial block of cell death. We compared side by side the mechanistic differences in these cells in response to AT and GT3.

Methods

The effects of GT3 and AT were studied on androgen sensitive LNCaP and androgen independent PC-3 prostate cancer cells. Their cytotoxic effects were analyzed via MTT and confirmed by metabolic assays measuring ATP. Cellular pathways were studied by immunoblot. Quantitative analysis and the determination of relationships between cell signaling events were analyzed for both agents tested. Non-cancerous prostate RWPE-1 cells were also included as a control.

Results

The RAF/RAS/ERK pathway was significantly activated by GT3 in LNCaP and PC-3 cells but not by AT. This activation is essential for the apoptotic affect by GT3 as demonstrated the complete inhibition of apoptosis by MEK1 inhibitor U0126. Phospho-c-JUN was upregulated by GT3 but not AT. No changes were observed on AKT for either agent, and no release of cytochrome c into the cytoplasm was detected. Caspases 9 and 3 were efficiently activated by GT3 on both cell lines irrespective of androgen sensitivity, but not in cells dosed with AT. Cell viability of non-cancerous RWPE-1 cells was affected neither by GT3 nor AT.

Conclusions

c-JUN is a recognized master regulator of apoptosis as shown previously in prostate cancer. However, the mechanism of action of GT3 in these cells also include a significant activation of ERK which is essential for the apoptotic effect of GT3. The activation of both, ERK and c-JUN, is required for apoptosis and may suggest a relevant step in ensuring circumvention of mechanisms of resistance related to the constitutive activation of MEK1.

Cholesterol induced autophagy via IRE1/JNK pathway promotes autophagic cell death in heart tissue

BACKGROUND

Cardiovascular diseases (CVDs), with highest mortality and morbidity rates, are the major cause of death in the world. Due to the limited information on heart tissue changes, mediated by hypercholesterolemia, we planned to investigate molecular mechanisms of endoplasmic reticulum (ER) stress and related cell death in high cholesterol fed rabbit model and possible beneficial effects of α-tocopherol.

METHODS

Molecular changes in rabbit heart tissue and cultured cardiomyocytes (H9c2 cells) were measured by western blotting, qRT-PCR, immunflouresence and flow cytometry experiments. Histological modifications were assessed by light and electron microscopes, while degradation of mitochondria was quantified through confocal microscope.

RESULTS

Feeding rabbits 2% cholesterol diet for 8 weeks and treatment of cultured cardiomyocytes with 10 μg/mL cholesterol for 3 h induced excessive autophagic activity via IRE1/JNK pathway. While no change in ER-associated degradation (ERAD) and apoptotic cell death were determined, electron and confocal microscopy analyses in cholesterol supplemented rabbits revealed significant parameters of autophagic cell death, including cytoplasmic autophagosomes, autolysosomes and organelle loss in juxtanuclear area as well as mitochondria engulfment by autophagosome. Either inhibition of ER stress or JNK in cultured cardiomyocytes or α-tocopherol supplementation in rabbits could counteract the effects of cholesterol.

CONCLUSION

Our findings underline the essential role of hypercholesterolemia in stimulating IRE1/JNK branch of ER stress response which then leads to autophagic cell death in heart tissue. Results also showed α-tocopherol as a promising regulator of autophagic cell death in cardiomyocytes.