Effects of vitamin E on peroxisome proliferator-activated receptor γ and nuclear factor-erythroid 2-related factor 2 in hypercholesterolemia-induced atherosclerosis

Effect of Vitamin E on Transcriptomic Alterations in Alzheimer's Disease

Research into ageing is focused on understanding why some people can maintain cognitive ability and others lose autonomy, affecting their quality of life. Studies have revealed that age-related neurodegenerative disorders like Alzheimer's disease (AD) are now major causes of death among the elderly, surpassing malignancy. This review examines the effects of vitamin E on transcriptomic changes in ageing and neurodegenerative diseases, using AD as an example, and how different transcriptome profiling techniques can shape the results. Despite mixed results from transcriptomic studies on AD patients' brains, we think advanced technologies could offer a more detailed and accurate tool for such analysis. Research has also demonstrated the role of antioxidant modifiers in preventing AD. This review will explore the key findings regarding AD and its modulation by vitamin E, emphasizing the shift in its epidemiology during the ageing process.

Nrf2-Mediated Dichotomy in the Vascular System: Mechanistic and Therapeutic Perspective

Nuclear factor-erythroid 2-related factor 2 (Nrf2), a transcription factor, controls the expression of more than 1000 genes that can be clustered into different categories with distinct functions ranging from redox balance and metabolism to protein quality control in the cell. The biological consequence of Nrf2 activation can be either protective or detrimental in a context-dependent manner. In the cardiovascular system, most studies have focused on the protective properties of Nrf2, mainly as a key transcription factor of antioxidant defense. However, emerging evidence revealed an unexpected role of Nrf2 in mediating cardiovascular maladaptive remodeling and dysfunction in certain disease settings. Herein we review the role of Nrf2 in cardiovascular diseases with a focus on vascular disease. We discuss the negative effect of Nrf2 on the vasculature as well as the potential underlying mechanisms. We also discuss the clinical relevance of targeting Nrf2 pathways for the treatment of cardiovascular and other diseases.

Antiretroviral Therapy-Induced Dysregulation of Gene Expression and Lipid Metabolism in HIV+ Patients: Beneficial Role of Antioxidant Phytochemicals

Human immunodeficiency virus (HIV) infection has continued to be the subject of study since its discovery nearly 40 years ago. Significant advances in research and intake of antiretroviral therapy (ART) have slowed the progression and appearance of the disease symptoms and the incidence of concomitant diseases, which are the leading cause of death in HIV+ persons. However, the prolongation of ART is closely related to chronic degenerative diseases and pathologies caused by oxidative stress (OS) and alterations in lipid metabolism (increased cholesterol levels), both of which are conditions of ART. Therefore, recent research focuses on using natural therapies to diminish the effects of ART and HIV infection: regulating lipid metabolism and reducing OS status. The present review summarizes current information on OS and cholesterol metabolism in HIV+ persons and how the consumption of certain phytochemicals can modulate these. For this purpose, MEDLINE and SCOPUS databases were consulted to identify publications investigating HIV disease and natural therapies and their associated effects.

Oxidative Stress: Meeting Multiple Targets in Pathogenesis of Vascular Endothelial Dysfunction

Vascular endothelium is the innermost lining of blood vessels, which maintains vasoconstriction and vasodilation. Loss of vascular tone is a hallmark for cardiovascular disorders. Though there are numerous factors, such as over activation of renin angiotensin aldosterone system, kinases, growth factors, etc. play crucial role in induction and progression of vascular abrasion. Interestingly, dysregulation of these pathways either enhances the intensity of oxidative stress, or these pathways are affected by oxidative stress. Thus, oxidative stress has been considered a key culprit in the progression of vascular endothelial dysfunction. Oxidative stress induced by reactive oxygen and nitrogen species causes abnormal gene expression, alteration in signal transduction, and the activation of pathways leading to induction and progression of vascular injury. In addition, numerous antioxidants have been noted to possess promising therapeutic potential in preventing the development of vascular endothelial dysfunction. Therefore, we have focused on current perspectives in oxidative stress signalling to evaluate common biological processes whereby oxidative stress plays a crucial role in the progression of vascular endothelial dysfunction.

Co-Administration of Vitamin E and Atorvastatin Improves Insulin Sensitivity and Peroxisome Proliferator-Activated Receptor-γ Expression in Type 2 Diabetic Patients: A Randomized Double-Blind Clinical Trial

Background

Negative effects of statins on glucose metabolism have been reported. The present study aimed to investigate the effects of co-administration of vitamin E and atorvastatin on glycemic control in hyperlipidemic patients with type 2 diabetes mellitus (T2DM).

Methods

A randomized double-blind clinical trial was conducted at Vali-e-Asr Teaching Hospital (Zanjan, Iran) from July 2017 to March 2018. A total of 30 T2DM female patients were allocated to two groups, namely atorvastatin with placebo (n=15) and atorvastatin with vitamin E (n=15). The patients received daily 20 mg atorvastatin and 400 IU vitamin E or placebo for 12 weeks. Anthropometric and biochemical measures were recorded pre- and post-intervention. Peroxisome proliferator-activated receptor-γ (PPAR-γ) expression was measured in peripheral blood mononuclear cells (PBMCs). Independent sample t test and paired t test were used to analyze between- and within-group variables, respectively. The analysis of covariance (ANCOVA) was used to adjust the effect of baseline variables on the outcomes. P<0.05 was considered statistically significant.

Results

After baseline adjustment, there was a significant improvement in homeostatic model assessment for insulin resistance (HOMA-IR) (P=0.04) and serum insulin (P<0.001) in the atorvastatin with vitamin E group compared to the atorvastatin with the placebo group. In addition, co-administration of vitamin E with atorvastatin significantly upregulated PPAR-γ expression (OR=5.4, P=0.04) in the PBMCs of T2DM patients.

Conclusion

Co-administration of vitamin E and atorvastatin reduced insulin resistance and improved PPAR-γ mRNA expression. Further studies are required to substantiate our findings.

Trial registration number

IRCT 20170918036256N.

Autophagy, Pyroptosis, and Ferroptosis: New Regulatory Mechanisms for Atherosclerosis

Atherosclerosis is a chronic inflammatory disorder characterized by the gradual buildup of plaques within the vessel wall of middle-sized and large arteries. The occurrence and development of atherosclerosis and the rupture of plaques are related to the injury of vascular cells, including endothelial cells, smooth muscle cells, and macrophages. Autophagy is a subcellular process that plays an important role in the degradation of proteins and damaged organelles, and the autophagy disorder of vascular cells is closely related to atherosclerosis. Pyroptosis is a proinflammatory form of regulated cell death, while ferroptosis is a form of regulated nonapoptotic cell death involving overwhelming iron-dependent lipid peroxidation. Both of them exhibit distinct features from apoptosis, necrosis, and autophagy in morphology, biochemistry, and genetics. However, a growing body of evidence suggests that pyroptosis and ferroptosis interact with autophagy and participate in the development of cancers, degenerative brain diseases and cardiovascular diseases. This review updated the current understanding of autophagy, pyroptosis, and ferroptosis, finding potential links and their effects on atherogenesis and plaque stability, thus providing ways to develop new pharmacological strategies to address atherosclerosis and stabilize vulnerable, ruptured plaques.

Targeting dyslipidemia with antioxidative vitamins C, D, and E; a systematic review of meta-analysis studies: Dyslipidemia and antioxidative vitamins

Background

There is controversial evidence for the beneficial effects of antioxidative vitamins (vits) on dyslipidemia. In this regard, we aimed to systematically review all meta-analyses of trials on this topic.

Methods

We comprehensively searched PubMed, Web of Science, Scopus, and Cochrane Library databases until January 2021 to explore the published English meta-analyses of trials conducted to assess the effects of single or combined vits C, D and E consumption on lipid profile. The meta-analyses of observational, in vivo/in vitro, or case-report studies were excluded. Search results were reported based on the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) flowchart.

Results

Overall, 25 meta-analyses including 32,177 individuals with different underlying disorders met our inclusion criteria. Numerous studies had assessed supplementation with Vit-D or its combination with other agents on lipid profile. Consumption of 400 IU/day (d) to 50,000 IU/week (w) Vit-D for at least eight weeks improved the levels of total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and triglycerides (TG) in type 2 diabetes mellitus or polycystic ovary syndrome (PCOS) patients. This treatment reduced the levels of TC and TG in patients with chronic kidney disease. A significant increase in high-density lipoprotein cholesterol (HDL-C) levels was only observed in coronary artery disease patients. Sole intake of 500-2000 mg/d Vit-C for at least 3 weeks improved LDL-C and TG values in hypercholesterolemic patients. Nevertheless, sole intake of Vit-E had controversial effects on lipid profile. The combination of 400-1800 IU/d omega-3 free fatty acid (FFA) and 400 IU/d Vit-E significantly reduced the levels of LDL-C and TG in overweight individuals, without any significant effect on other components. A significant improvement of TG values was observed after consumption of 1000-2000 mg/d omega-3 FFA plus 400 IU/d Vit-E along with 50,000 IU/each 2w Vit-D for at least 6 weeks in diabetic patients.

Conclusion

The beneficial effects of antioxidative vitamins (C, D, E) or their combination with other agents on lipid profile varied based on their dosage, intake duration, and the health status of the individuals.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40200-021-00919-8.

Apoptosis and Cell Proliferation Markers in Inflammatory-Fibroproliferative Diseases of the Vessel Wall (Review)

Apoptosis is the main feature of inflammatory-fibroproliferative disorders of the vessel wall. Studies in animal models have shown that smooth muscle cells (SMCs) cultured from endarterectomy specimens from the affected area proliferate more slowly and display higher apoptotic indices than SMCs derived from the normal vessel wall. Apoptotic cells were found in the destabilized atherosclerotic plaques, as well as in the samples with restenosis of the reconstruction area.

Injury to the vessel wall causes two waves of apoptosis. The first wave is the rapid apoptosis in the media that occurs within a few hours after injury and leads to a marked reduction in the number of vascular wall cells. The second wave of apoptosis occurs much later (from several days to weeks) and is limited by the SMCs within the developing neointima. Up to 14% of the neointimal SMCs undergo apoptosis 20 days after balloon angioplasty. Ligation of the external carotid artery in a rabbit model led to a marked decrease in blood flow in the common carotid artery, which correlated with the increased apoptosis of endothelial cells and SMCs.

Angioplasty-induced death of SMCs is regulated by a redox-sensitive signaling pathway, and topical administration of antioxidants can minimize vascular cell loss. On the whole, studies show that apoptosis is prevalent in vascular lesions, controlling the viability of both inflammatory and vascular cells, determining the cellular composition of the vessel wall. The main markers of apoptosis (Fas, Fas ligand, p53, Bcl-2, Bax) and cell proliferation (toll receptor) have been considered in the current review.

Impact of Dietary Lipids on the Reverse Cholesterol Transport: What We Learned from Animal Studies

Reverse cholesterol transport (RCT) is a physiological mechanism protecting cells from an excessive accumulation of cholesterol. When this process begins in vascular macrophages, it acquires antiatherogenic properties, as has been widely demonstrated in animal models. Dietary lipids, despite representing a fundamental source of energy and exerting multiple biological functions, may induce detrimental effects on cardiovascular health. In the present review we summarize the current knowledge on the mechanisms of action of the most relevant classes of dietary lipids, such as fatty acids, sterols and liposoluble vitamins, with effects on different steps of RCT. We also provide a critical analysis of data obtained from experimental models which can serve as a valuable tool to clarify the effects of dietary lipids on cardiovascular disease.

Dietary nutrients and their control of the redox bioenergetic networks as therapeutics in redox dysfunctions sustained pathologies

Electrons exchange amongst the chemical species in an organism is a pivotal concomitant activity carried out by individual cells for basic cellular processes and continuously contribute towards the maintenance of bioenergetic networks plus physiological attributes like cell growth, phenotypic differences and nutritional adaptations. Humans exchange matter and energy via complex connections of metabolic pathways (redox reactions) amongst cells being a thermodynamically open system. Usually, these reactions are the real lifeline and driving forces of health and disease in the living entity. Many shreds of evidence support the secondary role of reactive species in the cellular process of control apoptosis and proliferation. Disrupted redox mechanisms are seen in malaises, like degenerative and metabolic disorders, cancerous cells. This review targets the importance of redox reactions in the body's normal functioning and the effects of its alterations in cells to obtain a better understanding. Understanding the redox dynamics in a pathological state can provide an opportunity for cure or diagnosis at the earlier stage and serve as an essential biomarker to predict in advance to give personalized therapy. Understanding redox metabolism can also highlight the use of naturally available antioxidant in the form of diet.

alpha-Tocopherol supplementation reduces inflammation and apoptosis in high cholesterol mediated nonalcoholic steatohepatitis

Inflammation and apoptosis signaling are crucial steps in the progression from nonalcoholic fatty liver disease (NAFLD) to nonalcoholic steatohepatitis (NASH). Alpha-tocopherol, the most active form of vitamin E, is an important modulator of signaling mechanisms, but its involvement to cholesterol-induced NASH pathogenesis remains poorly defined. Herein we have reported a novel effect of α-tocopherol in the transition from hepatic steatosis to NASH. High cholesterol diet alone (without α-tocopherol) in rabbits elevated NASH development as indicated by increased inflammatory response, apoptotic activity and liver fibrosis. Such elevation results from induction of signaling mechanisms since the expressions of IL1β, phospho c-Jun/c-Jun ratio, JNK, caspase 9, CHOP and Bax were increased, and recruitment of macrophage, α-smooth muscle actin (α-SMA) and COL1A1 into the liver tissue were induced. Alpha-tocopherol supplementation inhibited inflammatory response, apoptosis and fibrosis development without affecting lipid accumulation in high cholesterol-induced NASH. Specifically, α-tocopherol lowered the inflammatory level as observed by reduced macrophage infiltration and JNK/c-Jun signaling. Lower inflammatory status co-occurred with the reduction of CHOP and Bax expressions as well as fibrosis-related COL1A1 and α-SMA levels. Taken together, α-tocopherol supplementation inhibits cholesterol-induced NASH development by lowering JNK/c-Jun/inflammation axis in addition to JNK/CHOP/apoptosis signaling, which might contribute to resistance against NAFLD/NASH transition.

PDSS2 Inhibits the Ferroptosis of Vascular Endothelial Cells in Atherosclerosis by Activating Nrf2

ABSTRACT

Cardiovascular disease ranks the leading cause of mortality worldwide. Prenyldiphosphate synthase subunits collectively participate in the formation and development of atherosclerosis (AS). This study aimed to investigate the role of PDSS2 in AS and its underlying mechanisms. Human coronary artery endothelial cells (HCAECs) were treated with oxidized low-density lipoprotein to establish the AS model. The gene expression levels were determined by qRT-PCR, Western blot, and ELISA. CCK-8, colony formation was applied to determine the proliferation of HCAECs. Chromatin immunoprecipitation assay and luciferase assay were applied to verify the interaction between PDSS2 and Nrf2. The results showed that the serum levels of PDSS2 and Nrf2 were decreased in patients with AS. Overexpression of PDSS2 suppressed the release of reactive oxygen species, iron content and ferroptosis of HCAECs, and promoted the proliferation of HCAECs. Moreover, PDSS2 activated antioxidant Nrf2. PDSS2 interacted with Nrf2 to alleviate the ferroptosis of HCAECs. However, knockdown of Nrf2 alleviated the effects of PDSS2 on the proliferation and ferroptosis of HCAECs. In vivo assays, overexpression of PDSS2 and Nrf2 suppressed the progression of AS. In conclusion, overexpression of PDSS2 suppressed the ferroptosis of HCAECs by promoting the activation of Nrf2 pathways. Thence PDSS2 may play a cardio-protective role in AS.

Role of Oxidative Stress in the Pathogenesis of Non-Alcoholic Fatty Liver Disease: Implications for Prevention and Therapy

Oxidative stress (OxS) is considered a major factor in the pathophysiology of inflammatory chronic liver diseases, including non-alcoholic liver disease (NAFLD). Chronic impairment of lipid metabolism is closely related to alterations of the oxidant/antioxidant balance, which affect metabolism-related organelles, leading to cellular lipotoxicity, lipid peroxidation, chronic endoplasmic reticulum (ER) stress, and mitochondrial dysfunction. Increased OxS also triggers hepatocytes stress pathways, leading to inflammation and fibrogenesis, contributing to the progression of non-alcoholic steatohepatitis (NASH). The antioxidant response, regulated by the Nrf2/ARE pathway, is a key component in this process and counteracts oxidative stress-induced damage, contributing to the restoration of normal lipid metabolism. Therefore, modulation of the antioxidant response emerges as an interesting target to prevent NAFLD development and progression. This review highlights the link between disturbed lipid metabolism and oxidative stress in the context of NAFLD. In addition, emerging potential therapies based on antioxidant effects and their likely molecular targets are discussed.

Autophagy blockage promotes the pyroptosis of ox-LDL-treated macrophages by modulating the p62/Nrf2/ARE axis

Atherosclerosis, a chronic comprehensive cardiovascular disease, is characterized by the lipid infiltration, formation of foam cells derived from macrophages and inflammation in the vessel wall. Substantial evidence confirms that the activity of autophagic bodies plays a pivot role in regulating cell deaths, but the mechanisms of autophagy to regulate the pyroptosis of macrophages in atherosclerosis remain unclear. In our study, we explored that ox-LDL decreased the cell viability and destroyed the integrity of cell membrane, resulting in the pyroptosis of THP-1 derived macrophages in a dose-dependent manner. Western blotting, qRT-PCR and ELISA also showed that chloroquine (CQ) could up-regulate the expression of p62 through impairing autophagy and induce the pyroptosis of macrophages treated by ox-LDL, as evidenced by the decrease of cell viability and membrane integrity, and the increase of pro-caspase-1, GSDMD, and proinflammatory factors IL-1β and IL-18. Further researches demonstrated that Nrf2, a nuclear factor activated by p62, was linked to macrophage pyroptosis. Overactivating or suppressing Nrf2/ARE signaling would correspondingly aggravate or alleviate pyroptosis, in which the level of p62 was regulated by Nrf2 feedback. Then, bioinformatic analysis verified that there was a close interaction between p62, Nrf2/ARE signaling proteins and pyroptosis-related proteins. Taken together, our results show that blocking autophagy promotes the pyroptosis of ox-LDL-treated macrophages via the p62/Nrf2/ARE axis, providing a novel therapeutic target for atherosclerosis.

Antioxidant alterations link polycyclic aromatic hydrocarbons to blood pressure in children

Exposure to polycyclic aromatic hydrocarbons (PAHs) is associated with changes in blood pressure. However, the association is controversial in different studies, and antioxidants' roles involved in it remain unclear. To investigate the associations among PAH exposure, blood pressure, and antioxidant concentrations, we recruited 403 children (2-7 years old), of which 203 were from Guiyu, an e-waste-recycling area (exposed group), and 200 were from Haojiang, a nearby non-e-waste area (reference group). Levels of blood pressure, plasma vitamin E, serum superoxide dismutase (SOD), serum glutathione peroxidase (GPx), and eight urinary hydroxylated PAHs (OH-PAHs) were measured. Compared with Haojiang children, Guiyu children had higher urinary OH-PAH concentrations but lower systolic pressure, pulse pressure, serum SOD concentration, and serum GPx concentration (all P < 0.05). PAH exposure was associated with lower systolic pressure, pulse pressure, SOD (adjusted β = -0.091, -0.104 and -0.154, respectively, all P < 0.05, in all children), GPx (adjusted β_{∑7LMW-OH-PAHs-T3} = -0.332, only in Haojiang children) and vitamin E (adjusted OR_{∑7LMW-OH-PAHs} = 0.838, 95% CI: 0.706, 0.995, only in Guiyu children). Serum SOD and GPx were associated with higher blood pressure (β_SOD-T2 for diastolic pressure = 0.215 in all children, β_SOD-T3 for systolic pressure = 0.193 in all children, β_SOD-T3 for pulse pressure = 0.281 in high-∑₈OH-PAHs children, β_GPx-T2 = 0.283 and β_GPx-T3 = 0.289 for diastolic pressure in Haojiang children, all P < 0.05). Interactions between PAHs and vitamin E were associated with lower systolic pressure and pulse pressure; simple effects of vitamin E to raise systolic pressure and pulse pressure were only significant in low-∑₈OH-PAHs children. Our results indicate that PAH exposure, especially at high levels, and further antioxidant-decrease are potential risk factors for blood-pressure decrease in children; vascular function of PAH-exposed children may be impaired, manifesting as disordered blood pressure.

Artesunate inhibits atherosclerosis by upregulating vascular smooth muscle cells-derived LPL expression via the KLF2/NRF2/TCF7L2 pathway

Lipoprotein lipase (LPL) plays a central role in hydrolyzing triglyceride and its deficiency leads to atherosclerosis. Artesunate (ART), a derivative of artemisinin, has been demonstrated that ART reduces the formation of atherosclerotic plaques. However, it remains unclear whether ART-alleviated atherosclerotic lesion is involved in regulating lipid metabolism. ApoE^-/- mice were fed a high-fat diet to form atherosclerotic plaques and then injected with artesunate or not. Oil Red O, HE and Masson staining were performed to assess atherosclerotic plaques. Both Western blot and qRT-PCR were applied to detect protein expression. The Luciferase reporter gene and Chromatin immunoprecipitation assays were used to assess the interaction between proteins. Immunofluorescence assay was performed to show the localization of target proteins. In vitro, our data shown that ART increased LPL expression and inhibition of NRF2 blocked the binding of TCF7L2 to LPL promoter region in VSMCs. Downregulated Klf2 could decrease the nuclear enrichment of NRF2, TCF7L2 and LPL expression. In vivo, ART decreased atherosclerotic plaque formation and increased VSMC counts and LPL expression within atherosclerotic plaques. We observed the reduced tendency of serum lipids, and increased in serum LPL activity in mice. In support of vitro data, the markedly increased KLF2, TCF7L2 and LPL expression have been detected in aorta. Our study suggests that ART may be a novel therapeutic drug for inhibition of atherosclerotic plaque formation. The molecular mechanism may involve in upregulation of LPL expression via the KLF2/NRF2/TCF7L2 pathway in VSMCs.

Garcinoic acid prevents β-amyloid (Aβ) deposition in the mouse brain

Garcinoic acid (GA or δ-T3-13'COOH), is a natural vitamin E metabolite that has preliminarily been identified as a modulator of nuclear receptors involved in β-amyloid (Aβ) metabolism and progression of Alzheimer's disease (AD). In this study, we investigated GA's effects on Aβ oligomer formation and deposition. Specifically, we compared them with those of other vitamin E analogs and the soy isoflavone genistein, a natural agonist of peroxisome proliferator–activated receptor γ (PPARγ) that has therapeutic potential for managing AD. GA significantly reduced Aβ aggregation and accumulation in mouse cortical astrocytes. Similarly to genistein, GA up-regulated PPARγ expression and apolipoprotein E (ApoE) efflux in these cells with an efficacy that was comparable with that of its metabolic precursor δ-tocotrienol and higher than those of α-tocopherol metabolites. Unlike for genistein and the other vitamin E compounds, the GA-induced restoration of ApoE efflux was not affected by pharmacological inhibition of PPARγ activity, and specific activation of pregnane X receptor (PXR) was observed together with ApoE and multidrug resistance protein 1 (MDR1) membrane transporter up-regulation in both the mouse astrocytes and brain tissue. These effects of GA were associated with reduced Aβ deposition in the brain of TgCRND8 mice, a transgenic AD model. In conclusion, GA holds potential for preventing Aβ oligomerization and deposition in the brain. The mechanistic aspects of GA's properties appear to be distinct from those of other vitamin E metabolites and of genistein.

High-throughput profiling reveals perturbation of endoplasmic reticulum stress-related genes in atherosclerosis induced by high-cholesterol diet and the protective role of vitamin E

Formation of atherosclerotic plaques, called atherogenesis, is a complex process affected by genetic and environmental factors. It was proposed that endoplasmic reticulum (ER) stress is an important factor in the pathogenesis of atherosclerosis and that vitamin E affects atherosclerotic plaque formation via its antioxidant properties. Here, we investigated ER stress-related molecular mechanisms in high-cholesterol diet (HCD, 2%)-induced atherosclerosis model and the role of vitamin E supplementation in it, beyond its antioxidant properties. The consequences of HCD and vitamin E supplementation were examined by determining protein levels of ER stress markers in aortic tissues. As vitamin E supplementation acts on several unfolded protein response (UPR) factors, it decreased ER stress induced by HCD. To elucidate the associated pathways, gene expression profiling was performed, revealing differentially expressed genes enriched in ER stress-related pathways such as the proteasome and the apoptosis pathways. We further assessed the proteasomal activity impaired by HCD in the aorta and showed that vitamin E reversed it to that of control animals. Overall, the study characterized the effects of HCD and vitamin E on ER stress-related gene expression, revealing the role of proteolytic systems during atherogenesis.

A Mitochondrial Approach to Cardiovascular Risk and Disease

BACKGROUND

Cardiovascular diseases (CVDs) are a leading risk factor for mortality worldwide and the number of CVDs victims is predicted to rise through 2030. While several external parameters (genetic, behavioral, environmental and physiological) contribute to cardiovascular morbidity and mortality; intrinsic metabolic and functional determinants such as insulin resistance, hyperglycemia, inflammation, high blood pressure and dyslipidemia are considered to be dominant factors.

METHODS

Pubmed searches were performed using different keywords related with mitochondria and cardiovascular disease and risk. In vitro, animal and human results were extracted from the hits obtained.

RESULTS

High cardiac energy demand is sustained by mitochondrial ATP production, and abnormal mitochondrial function has been associated with several lifestyle- and aging-related pathologies in the developed world such as diabetes, non-alcoholic fatty liver disease (NAFLD) and kidney diseases, that in turn can lead to cardiac injury. In order to delay cardiac mitochondrial dysfunction in the context of cardiovascular risk, regular physical activity has been shown to improve mitochondrial parameters and myocardial tolerance to ischemia-reperfusion (IR). Furthermore, pharmacological interventions can prevent the risk of CVDs. Therapeutic agents that can target mitochondria, decreasing ROS production and improve its function have been intensively researched. One example is the mitochondria-targeted antioxidant MitoQ10, which already showed beneficial effects in hypertensive rat models. Carvedilol or antidiabetic drugs also showed protective effects by preventing cardiac mitochondrial oxidative damage.

CONCLUSION

This review highlights the role of mitochondrial dysfunction in CVDs, also show-casing several approaches that act by improving mitochondrial function in the heart, contributing to decrease some of the risk factors associated with CVDs.

Impact of natural products on the cholesterol transporter ABCA1

ETHNOPHARMACOLOGICAL RELEVANCE

In different countries and areas of the world, traditional medicine has been and is still used for the treatment of various disorders, including chest pain or liver complaints, of which we now know that they can be linked with altered lipid and cholesterol homeostasis. As ATP-binding cassette transporter A1 (ABCA1) plays an essential role in cholesterol metabolism, its modulation may be one of the molecular mechanisms responsible for the experienced benefit of traditional recipes. Intense research activity has been dedicated to the identification of natural products from traditional medicine that regulate ABCA1 expression.

AIMS OF THE REVIEW

This review surveys natural products, originating from ethnopharmacologically used plants, fungi or marine sources, which influence ABCA1 expression, providing a reference for future study.

MATERIALS AND METHODS

Information on regulation of ABCA1 expression by natural compounds from traditional medicine was extracted from ancient and modern books, materia medica, and electronic databases (PubMed, Google Scholar, Science Direct, and ResearchGate).

RESULTS

More than 60 natural compounds from traditional medicine, especially traditional Chinese medicine (TCM), are reported to regulate ABCA1 expression in different in vitro and in vivo models (such as cholesterol efflux and atherosclerotic animal models). These active compounds belong to the classes of polyketides, terpenoids, phenylpropanoids, tannins, alkaloids, steroids, amino acids and others. Several compounds appear very promising in vivo, which need to be further investigated in animal models of diseases related to ABCA1 or in clinical studies.

CONCLUSION

Natural products from traditional medicine constitute a large promising pool for compounds that regulate ABCA1 expression, and thus may prevent/treat diseases related to cholesterol metabolism, like atherosclerosis or Alzheimer's disease. In many cases, the molecular mechanisms of these natural products remain to be investigated.

Nrf2 dysfunction and impaired cellular resilience to oxidative stressors in the aged vasculature: from increased cellular senescence to the pathogenesis of age-related vascular diseases

Aging is associated with increased oxidative stress in vascular endothelial and smooth muscle cells, which contribute to the development of a wide range of diseases affecting the circulatory system in older adults. There is growing evidence that in addition to increased production of reactive oxygen species (ROS), aging critically impairs pathways determining cellular resilience to oxidative stressors. In young organisms, the evolutionarily conserved nuclear factor-erythroid-2-related factor 2 (Nrf2)-mediated antioxidant response pathway maintains cellular reduction-oxidation homeostasis and promotes a youthful cellular phenotype by regulating the transcription of an array of cytoprotective (antioxidant, pro-survival, anti-inflammatory and macromolecular damage repair) genes. A critical mechanism by which increased ROS production and Nrf2 dysfunction promote vascular aging and exacerbate pathogenesis of age-related vascular diseases is induction of cellular senescence, an evolutionarily conserved cellular stress response mechanism. Senescent cells cease dividing and undergo distinctive phenotypic alterations, contributing to impairment of angiogenic processes, chronic sterile inflammation, remodeling of the extracellular matrix, and barrier dysfunction. Herein, we review mechanisms contributing to dysregulation of Nrf2-driven cytoprotective responses in the aged vasculature and discuss the multifaceted role of Nrf2 dysfunction in the genesis of age-related pathologies affecting the circulatory system, including its role in induction of cellular senescence. Therapeutic strategies that restore Nrf2 signaling and improve vascular resilience in aging are explored to reduce cardiovascular mortality and morbidity in older adults.

Molecular Understanding of the Cardiomodulation in Myocardial Infarction and the Mechanism of Vitamin E Protections

:

Myocardial infarction is a major cause of deaths globally. Modulation of several molecular mechanisms occurs during the initial stages of myocardial ischemia prior to permanent cardiac tissue damage, which involves both pathogenic as well as survival pathways in the cardiomyocyte. Currently, there is increasing evidence regarding the cardioprotective role of vitamin E in alleviating the disease. This fat-soluble vitamin does not only act as a powerful antioxidant; but it also has the ability to regulate several intracellular signalling pathways including HIF-1, PPAR-γ, Nrf-2, and NF-κB that influence the expression of a number of genes and their protein products. Essentially, it inhibits the molecular progression of tissue damage and preserves myocardial tissue viability. This review aims to summarize the molecular understanding of the cardiomodulation in myocardial infarction as well as the mechanism of vitamin E protection.

Baicalin protects mouse testis from injury induced by heat stress

Heat stress has been documented to reduce reproductive performance of female animals through injury to germ cells, with few studies available in male animals. The objectives of this study were to evaluate protective effects of baicalin on testicular tissue damage of mice subjected to heat stress and its related mechanisms. In this experiment, A total of forty mice were divided into four groups, including control group (C), baicalin group (B), heat stressed group (H) and heat stress with baicalin treatment (H + B) group. Morphological changes, activities of antioxidant enzymes and apoptosis-related parameters in the mice testes tissue were monitored. The results showed that the process of spermatogenesis in mice testis was impaired and the cellular apoptosis increased due to acute heat stress at 41 °C. Interestingly, the tissue damage was alleviated with the significant (P < 0.05) increase in the activities of SOD, CAT and GSH-Px enzymes, decrease (P < 0.05) in MDA content and number of cellular apoptosis recorded in mice of H + B group compared with those in mice from H group. In addition, the Fas, FasL and P-JNK protein expressions were significantly (P < 0.05) increased; and apaf-1, caspase-3, -9 were slightly expressed in the H group, while there was no difference in Bcl-2 expression, compared with C, B and H + B groups. The above results clearly indicate that heat stress induces macroscopic/apoptotic and oxidative changes in the testicular tissue of mice; these changes are alleviated by Baicalin through increasing anti-oxidative enzyme activities and possibly through blocking Fas/FasL pathway.

Chronic stress: a crucial promoter of cell apoptosis in atherosclerosis

Objective

Chronic stress may lead to augmented incidence rates of coronary and cerebrovascular diseases associated with atherosclerosis. However, few studies have focused on the effect of chronic stress on atherosclerosis plaque formation. Therefore, this study was designed to directly evaluate how chronic stress affects atherosclerosis.

Methods

Thirty rabbits were divided into three groups: the control group, balloon-injury operation + high-fat diet model group, and chronic stress + balloon-injury operation + high-fat diet model group. Physical and social stress were induced, and proteomic methods were applied to identify specific markers.

Results

After protein determination, the chronic stress + balloon-injury operation + high-fat diet model group exhibited significant upregulation of the following apoptosis-related proteins: UBE2K, caspase 3, caspase 9, BAX, P53, and FAS. In particular, real-time polymerase chain reaction showed that the protein expression of caspase 9 was significantly downregulated in the stress group compared with the non-stress groups. However, the other proteins showed significantly increased expression in the stress group.

Conclusion

Chronic stress may promote cell apoptosis in the physiopathologic process of atherosclerosis.

Vitamin E: Regulatory Role on Signal Transduction

Vitamin E modulates signal transduction pathways by several molecular mechanisms. As a hydrophobic molecule located mainly in membranes it contributes together with other lipids to the physical and structural characteristics such as membrane stability, curvature, fluidity, and the organization into microdomains (lipid rafts). By acting as the main lipid-soluble antioxidant, it protects other lipids such as mono- and poly-unsaturated fatty acids (MUFA and PUFA, respectively) against chemical reactions with reactive oxygen and nitrogen species (ROS and RNS, respectively) and prevents membrane destabilization and cellular dysfunction. In cells, vitamin E affects signaling in redox-dependent and redox-independent molecular mechanisms by influencing the activity of enzymes and receptors involved in modulating specific signal transduction and gene expression pathways. By protecting and preventing depletion of MUFA and PUFA it indirectly enables regulatory effects that are mediated by the numerous lipid mediators derived from these lipids. In recent years, some vitamin E metabolites have been observed to affect signal transduction and gene expression and their relevance for the regulatory function of vitamin E is beginning to be elucidated. In particular, the modulation of the CD36/FAT scavenger receptor/fatty acids transporter by vitamin E may influence many cellular signaling pathways relevant for lipid homeostasis, inflammation, survival/apoptosis, angiogenesis, tumorigenesis, neurodegeneration, and senescence. Thus, vitamin E has an important role in modulating signal transduction and gene expression pathways relevant for its uptake, distribution, metabolism, and molecular action that when impaired affect physiological and patho-physiological cellular functions relevant for the prevention of a number of diseases. © 2018 IUBMB Life, 71(4):456-478, 2019.

The effects of omega-3 fatty acids and vitamin E co-supplementation on gene expression related to inflammation, insulin and lipid in patients with Parkinson's disease: A randomized, double-blind, placebo-controlled trial

OBJECTIVE

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

PATIENTS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

CD36 expression in peripheral blood mononuclear cells reflects the onset of atherosclerosis

Together with complex genetic and environmental factors, increased serum cholesterol and ox-LDL levels are considered as major triggering factors of atherosclerosis. Mononuclear cell infiltration to the arterial wall and uptake of ox-LDL, which is facilitated by CD36 receptor through an uncontrolled manner, play a key role in foam cell formation followed by atherogenesis development. The aim of this study was to analyze if CD36 expression in peripheral blood mononuclear cells reflect its aortic tissue level in hypercholesterolemia. In this study, CD36 protein expression was evaluated in aortic specimens of cholesterol or cholesterol plus Vitamin E treated animals in relation to the immunohistochemical analyses for the HNE-protein adducts, as well as for smooth muscle actin and vimentin. The CD36 mRNA expression was determined by RT-PCR in PBMC of hypercholesterolemic rabbits and hypercholesterolemic versus normocholesterolemic individuals. Immunohistochemistry findings revealed that smooth muscle actin, smooth muscle vimentin, HNE-protein conjugates, and CD36 protein expressions were significantly increased in aorta of hypercholesterolemic group where foam cells were present. High cholesterol diet significantly induced CD36 mRNA expression in both rabbit aorta and PBMCs, while positive correlation between aortic and PBMC CD36 expression has been found. In addition, consistent with the rabbit model, CD36 mRNA expression levels in human PBMCs were significantly higher in hypercholesterolemic patients than in normocholesterolemic individuals. Taken together, these results demonstrate that the CD36 mRNA levels of PBMCs could reflect the CD36 mRNA levels in aorta and could be used as a biomarker for diagnosis of atherosclerotic burden. © 2018 BioFactors, 44(6):588-596, 2018.

Antioxidant and Oxidative Stress: A Mutual Interplay in Age-Related Diseases

Aging is the progressive loss of organ and tissue function over time. Growing older is positively linked to cognitive and biological degeneration such as physical frailty, psychological impairment, and cognitive decline. Oxidative stress is considered as an imbalance between pro- and antioxidant species, which results in molecular and cellular damage. Oxidative stress plays a crucial role in the development of age-related diseases. Emerging research evidence has suggested that antioxidant can control the autoxidation by interrupting the propagation of free radicals or by inhibiting the formation of free radicals and subsequently reduce oxidative stress, improve immune function, and increase healthy longevity. Indeed, oxidation damage is highly dependent on the inherited or acquired defects in enzymes involved in the redox-mediated signaling pathways. Therefore, the role of molecules with antioxidant activity that promote healthy aging and counteract oxidative stress is worth to discuss further. Of particular interest in this article, we highlighted the molecular mechanisms of antioxidants involved in the prevention of age-related diseases. Taken together, a better understanding of the role of antioxidants involved in redox modulation of inflammation would provide a useful approach for potential interventions, and subsequently promoting healthy longevity.

Vitamin E alleviates phoxim-induced toxic effects on intestinal oxidative stress, barrier function, and morphological changes in rats

Phoxim is an organic phosphorus pesticide that remains easily in the environment, such as human food and animal feed. The objective of this study was to explore the effect of vitamin E on phoxim-induced oxidative stress in the intestinal tissues of Sprague-Dawley (SD) rats. Forty-eight Sprague-Dawley rats were randomly assigned to a control group and three treatment groups: treatment group 1 (phoxim: 20 mg/kg·BW), treatment group 2 (phoxim: 180 mg/kg·BW), and treatment 3 (vitamin E + phoxim: 200 mg/kg·BW + 180 mg/kg·BW). Phoxim was given by gavage administration once a day for 28 days. The results showed that phoxim significantly reduced jejunum villus height in rats (P < 0.05), and decreased the mRNA expression of junction protein genes of rats, including Occlidin and Claudin-4 (P < 0.05). Phoxim reduced GSH content and T-AOC level in the intestinal mucosa (P < 0.05). The mRNA expression levels of oxidative stress-related genes (Nrf2 and GPx2) were decreased. The mRNA expression of SOD was significantly increased. In addition, phoxim increased the level of interleukin-6 (IL-6) in jejunum mucosa and significantly reduced the level of IL-8 in ileum mucosas, while significantly increased TNF-α secretion. The mRNA expression levels of IL-1β, IL-6, and IL-8 were significantly decreased, and mRNA expression of TNF-α was significantly increased (P < 0.05). Phoxim also increased the DNA expression of total cecal bacteria and Escherichia coli, inhibited the DNA expression of Lactobacillus and destroyed the intestinal barrier. Two hundred milligrams per kilogram BW vitamin E reduced the effect of phoxim on intestinal structure, alleviated the oxidative stress in intestinal tissue, and decreased the level of TNF-α. The mRNA expressions of antioxidative stress genes (SOD and GPx2) were significantly increased. The DNA expression level of Lactobacillus was significantly increased. In conclusion, vitamin E helped reduce the toxicity of organophosphate pesticides, such as phoxim on rat intestinal tissue.

The effects of magnesium and vitamin E co-supplementation on parameters of glucose homeostasis and lipid profiles in patients with gestational diabetes

BACKGROUND

Magnesium and vitamin E are known to exert multiple beneficial effects, such as anti-glycemic and anti-lipidemic properties. The aim of this study was to determine the effects of magnesium and vitamin E co-supplementation on metabolic status of women with gestational diabetes (GDM).

METHODS

This randomized, double-blinded, placebo-controlled trial was conducted among 60 subjects diagnosed with GDM, aged 18-40 years. Subjects were randomly allocated into two groups to receive 250 mg/day magnesium oxide plus 400 IU/day vitamin E supplements or placebo (n = 30 each group) for 6 weeks. Participants' blood samples were taken to determine their metabolic profiles.

RESULTS

Subjects who received magnesium plus vitamin E supplements had significantly lower fasting plasma glucose (β - 5.20 mg/dL; 95% CI, - 7.88, - 2.52; P = 0.002), serum insulin levels (β - 2.93 μIU/mL; 95% CI, - 5.68, - 0.18; P = 0.02) and homeostasis model of assessment-insulin resistance (β - 0.78; 95% CI, - 1.42, - 0.14; P = 0.01), and higher quantitative insulin sensitivity check index (β 0.01; 95% CI, 0.005, 0.02; P = 0.002) compared with placebo. In addition, magnesium plus vitamin E supplementation resulted in a significant reduction in serum triglycerides (β - 50.31 mg/dL; 95% CI, - 67.58, - 33.04; P < 0.001), VLDL- (β - 10.06 mg/dL; 95% CI, - 13.51, - 6.60; P < 0.001), total- (β - 26.10 mg/dL; 95% CI, - 41.88, - 10.33; P = 0.004), LDL- (β - 15.20 mg/dL; 95% CI, - 29.50, - 0.91; P = 0.03) and total-/HDL-cholesterol ratio (β - 0.46; 95% CI, - 0.72, - 0.19; P < 0.001) compared with placebo. Magnesium and vitamin E co-supplementation did not affect HDL-cholesterol levels.

CONCLUSIONS

Overall, magnesium and vitamin E co-supplementation for 6 weeks in women with GDM significantly improved glycemic control and lipid profiles, except for HDL-cholesterol levels.

CLINICAL TRIAL REGISTRATION NUMBER

http://www.irct.ir : IRCT20170513033941N24.

High Cholesterol Diet-Induced Changes in Oxysterol and Scavenger Receptor Levels in Heart Tissue

Involvement of high cholesterol and oxidative stress in cardiovascular diseases is well studied, as it can be hypothesized that various products originated from lipid peroxidation, such as oxysterols, or affected protein expression might lead to cardiomyocyte damage followed by the pathological modifications. Although oxidation of excessive cholesterol to oxysterols in elevated stress conditions is identified by a number of studies, the role of a high cholesterol diet in regulating fatty acid and oxysterol accumulation, together with scavenger receptor mRNA levels, in the heart remains little investigated. Our study provides a detailed analysis of the changes in fatty acid, oxysterol, and scavenger receptor profiles and its relation with histological alterations in the heart tissue. We evaluated alterations of fatty acid composition, by the GC-MS method, while 4β-, 25-, and 27-hydroxycholesterol and 7-ketocholesterol levels by means of LC-MS/MS in high cholesterol diet-fed rabbits. Additionally, a number of proteins related to lipid metabolism and scavenger receptor mRNA expressions were evaluated by Western blotting and RT-PCR. According to our in vivo results, a high cholesterol diet enhances a number of unsaturated fatty acids, oxysterols, and LXRα, in addition to CD36, CD68, CD204, and SR-F1 expressions while α-tocopherol supplementation decreases LXRα and SR expressions together with an increase in 27-hydroxycholesterol and ABCA1 levels. Our results indicated that the high cholesterol diet modulates proteins related to lipid metabolism, which might result in the malfunction of the heart and α-tocopherol shows its beneficial effects. We believe that this work will lead the generation of different theories in the development of heart diseases.

Mitochondria and cardiovascular diseases-from pathophysiology to treatment

Mitochondria are the source of cellular energy production and are present in different types of cells. However, their function is especially important for the heart due to the high demands in energy which is achieved through oxidative phosphorylation. Mitochondria form large networks which regulate metabolism and the optimal function is achieved through the balance between mitochondrial fusion and mitochondrial fission. Moreover, mitochondrial function is upon quality control via the process of mitophagy which removes the damaged organelles. Mitochondrial dysfunction is associated with the development of numerous cardiac diseases such as atherosclerosis, ischemia-reperfusion (I/R) injury, hypertension, diabetes, cardiac hypertrophy and heart failure (HF), due to the uncontrolled production of reactive oxygen species (ROS). Therefore, early control of mitochondrial dysfunction is a crucial step in the therapy of cardiac diseases. A number of anti-oxidant molecules and medications have been used but the results are inconsistent among the studies. Eventually, the aim of future research is to design molecules which selectively target mitochondrial dysfunction and restore the capacity of cellular anti-oxidant enzymes.

The effects of omega-3 and vitamin E co-supplementation on parameters of mental health and gene expression related to insulin and inflammation in subjects with polycystic ovary syndrome

OBJECTIVE

The aim of this study was to evaluate the effects of omega-3 and vitamin E co-supplementation on parameters of mental health and gene expression related to insulin and inflammation in subjects with polycystic ovary syndrome (PCOS).

METHODS

Forty PCOS women were allocated into two groups and treated with 1000mg omega-3 fatty acids plus 400 IU vitamin E supplements (n = 20) or placebo (n = 20) per day for 12 weeks. Parameters of mental health were recorded at baseline and after the 12-week intervention. Gene expression related to insulin and inflammation were measured in blood samples of PCOS women.

RESULTS

After the 12-week intervention, compared with the placebo, omega-3 and vitamin E co-supplementation led to significant improvements in beck depression inventory total score (- 2.2 ± 2.0 vs. - 0.2 ± 1.3, P = 0.001), general health questionnaire scores (- 5.5 ± 4.6 vs. - 1.0 ± 2.3, P < 0.001) and depression anxiety and stress scale scores (- 7.2 ± 5.2 vs. - 1.3 ± 1.3, P < 0.001). Compared with the placebo, omega-3 and vitamin E co-supplementation could up-regulate peroxisome proliferator-activated receptor gamma (PPAR-γ) expression (P = 0.04) in peripheral blood mononuclear cells (PBMC) of PCOS women. In addition, compared with the placebo, omega-3 and vitamin E co-supplementation down-regulated interleukin-8 (IL-8) (P = 0.003) and tumor necrosis factor alpha (TNF-α) expression (P = 0.001) in PBMC of PCOS women. There were no significant difference between-group changes in glucose transporter 1 (GLUT-1), IL-6 and transforming growth factor beta (TGF-β) in PBMC of PCOS women.

CONCLUSION

Omega-3 and vitamin E co-supplementation was effective in improving parameters of mental health, and gene expression of PPAR-γ, IL-8 and TNF-α of women with PCOS.

Insights on Localized and Systemic Delivery of Redox-Based Therapeutics

Reactive oxygen and nitrogen species are indispensable in cellular physiology and signaling. Overproduction of these reactive species or failure to maintain their levels within the physiological range results in cellular redox dysfunction, often termed cellular oxidative stress. Redox dysfunction in turn is at the molecular basis of disease etiology and progression. Accordingly, antioxidant intervention to restore redox homeostasis has been pursued as a therapeutic strategy for cardiovascular disease, cancer, and neurodegenerative disorders among many others. Despite preliminary success in cellular and animal models, redox-based interventions have virtually been ineffective in clinical trials. We propose the fundamental reason for their failure is a flawed delivery approach. Namely, systemic delivery for a geographically local disease limits the effectiveness of the antioxidant. We take a critical look at the literature and evaluate successful and unsuccessful approaches to translation of redox intervention to the clinical arena, including dose, patient selection, and delivery approach. We argue that when interpreting a failed antioxidant-based clinical trial, it is crucial to take into account these variables and importantly, whether the drug had an effect on the redox status. Finally, we propose that local and targeted delivery hold promise to translate redox-based therapies from the bench to the bedside.

An excess dietary vitamin E concentration does not influence Nrf2 signaling in the liver of rats fed either soybean oil or salmon oil

Background

Reactive oxygen species (ROS) are known to stimulate the activation of nuclear factor-erythroid 2-related factor-2 (Nrf2), the key regulator of the antioxidant and cytoprotective defense system in the body. The hypothesis underlying this study was that high dietary concentrations of vitamin E suppress Nrf2 activation, and thus could weaken the body’s antioxidative and cytoprotective capacity. As the effect of vitamin E on Nrf2 pathway might be influenced by concentrations of fatty acids susceptible to oxidation in the diet, we used also diets containing either soybean oil as a reference oil or salmon oil as a source of oil rich in n-3 polyunsatuated fatty acids.

Methods

Seventy-two rats were divided into 6 groups of rats which received diets with either 25, 250 or 2500 mg vitamin E/kg, with either soybean oil or salmon oil as dietary fat sources according to a bi-factorial experimental design. Electron spin resonance spectroscopy was used to determine ROS production in the liver. qPCR analysis and western blot were performed to examine the expression of Nrf2 target genes in the liver of rats.

Results

Rats fed the salmon oil diet with 25 mg vitamin E/kg showed a higher production of ROS in the liver than the 5 other groups of rats which did not differ in ROS production. Relative mRNA concentrations of NFE2L2 (encoding Nrf2), KEAP1 and various Nrf2 target genes, protein concentrations of glutathione peroxidase (GPX), heme oxygenase 1 (HO-1), NAD(P)H quinone dehydrogenase 1 (NQO1) and activities of the antioxidant enzymes GPX, superoxide dismutase and catalase were not influenced by the dietary vitamin E concentration. The dietary fat had also less effect on Nrf2 target genes and no effect on protein concentrations of GPX, HO-1, NQO1 and activities of antioxidant enzymes. Dietary vitamin E concentration and type of fat moreover had less effect on mRNA concentrations of genes and concentrations of proteins involved in the unfolded protein response, a pathway which is closely linked with activation of Nrf2.

Conclusion

We conclude that excess dietary concentrations of vitamin E do not suppress Nrf2 signaling, and thus do not weaken the endogenous antioxidant and cytoprotective capacity in the liver of rats.

Collaborative Power of Nrf2 and PPARγ Activators against Metabolic and Drug-Induced Oxidative Injury

Mammalian cells have evolved a unique strategy to protect themselves against oxidative damage induced by reactive oxygen species (ROS). Especially, two transcription factors, nuclear factor erythroid 2p45-related factor 2 (Nrf2) and peroxisome proliferator-activated receptor γ (PPARγ), have been shown to play key roles in establishing this cellular antioxidative defense system. Recently, several researchers reported ameliorating effects of pharmacological activators for these Nrf2 and PPARγ pathways on the progression of various metabolic disorders and drug-induced organ injuries by oxidative stress. In this review, general features of Nrf2 and PPARγ pathways in the context of oxidative protection will be summarized first. Then, a number of successful applications of natural and synthetic Nrf2 and PPARγ activators to the alleviation of pathological and drug-related oxidative damage will be discussed later.

Naturally Occurring Compounds: New Potential Weapons against Oxidative Stress in Chronic Kidney Disease

Oxidative stress is a well-described imbalance between the production of reactive oxygen species (ROS) and the antioxidant defense system of cells and tissues. The overproduction of free radicals damages all components of the cell (proteins, lipids, nucleic acids) and modifies their physiological functions. As widely described, this condition is a biochemical hallmark of chronic kidney disease (CKD) and may dramatically influence the progression of renal impairment and the onset/development of major systemic comorbidities including cardiovascular diseases. This state is exacerbated by exposure of the body to uremic toxins and dialysis, a treatment that, although necessary to ensure patients' survival, exposes cells to non-physiological contact with extracorporeal circuits and membranes with consequent mitochondrial and anti-redox cellular system alterations. Therefore, it is undeniable that counteracting oxidative stress machinery is a major pharmacological target in medicine/nephrology. As a consequence, in recent years several new naturally occurring compounds, administered alone or integrated with classical therapies and an appropriate lifestyle, have been proposed as therapeutic tools for CKD patients. In this paper, we reviewed the recent literature regarding the "pioneering" in vivo testing of these agents and their inclusion in small clinical trials performed in patients affected by CKD.

The Relationship between Environmental Tobacco Smoke Exposure and Cardiovascular Disease and the Potential Modifying Effect of Diet in a Prospective Cohort among American Indians: The Strong Heart Study

American Indians experience high rates of cardiovascular diseases (CVD). Environmental tobacco smoke (ETS) has been linked to CVD, possibly due to pro-inflammatory and oxidative stress pathways. We examined the relationship between self-reported exposure to ETS and fatal and nonfatal CVD incidence using Cox proportional hazards models among 1843 non-smoking American Indians participating in the Strong Heart Study. We also evaluated potential modifying effects of several dietary nutrients high in anti-inflammatory and anti-oxidant properties with ETS exposure on fatal and nonfatal CVD by creating interaction terms between ETS exposure and the dietary variable. Participants exposed to ETS had a higher hazard (hazard ratio: 1.22; 95% confidence interval, 1.03 to 1.44) for developing CVD compared to persons not exposed. Interaction analyses suggested stronger effects of ETS on CVD incidence among those consuming diets lower in vitamin E as compared to those consuming higher amounts, particularly on the additive scale. Additional research is recommended to clarify whether public health prevention strategies should simultaneously target reductions in ETS exposures and improvements in diets that may exceed the expected benefits of targeting these risk factors separately.

Beta-sitosterol upregulated paraoxonase-1 via peroxisome proliferator-activated receptor-γ in irradiated rats

This study was designed to evaluate the effect of beta-sitosterol (BS) on the peroxisome proliferator-activated receptor gamma (PPAR-γ) gene expression role in the activity of paraoxonase (PON-1) enzyme in oxidative stress status of irradiated rats. Animals were exposed to whole body γ-radiation single dose 6 Gy and received BS dose (40 mg·(kg body mass)^-1·day ^-1, orally). In liver tissue, gene expression of PPAR-γ ligand was determined. Oxidative stress marker (malondialdehyde, MDA) and antioxidant enzyme activities (superoxide dismutase (SOD), catalase (CAT), PON-1, and arylesterase (ARE)) were assayed in serum and liver tissue. Also, serum lipid profile (cholesterol, triglycerides (TG), low-density lipoprotein cholesterol (LDL-c), and high-density lipoprotein cholesterol (HDL-c)) was measured. In irradiated animals that received BS, expression of PPAR-γ ligand increase significantly associated with increase in PON-1 and ARE enzyme activities. Also, the activities of SOD, CAT enzymes, and HDL-c levels display elevation. By contrast, significant decrease in MDA content, cholesterol, TG, and LDL-c levels were revealed after BS administration. Our findings in this study provide the evidence that BS has radio-protective effect via regulating the gene expression of PPAR-γ, causing an increase in PON-1 and ARE enzyme activities. This action of BS is due to its free radical scavenging properties, antioxidant effect, lowering of cholesterol, and PPAR-γ agonist properties.

Vitamin E: Emerging aspects and new directions

The discovery of vitamin E will have its 100th anniversary in 2022, but we still have more questions than answers regarding the biological functions and the essentiality of vitamin E for human health. Discovered as a factor essential for rat fertility and soon after characterized for its properties of fat-soluble antioxidant, vitamin E was identified to have signaling and gene regulation effects in the 1980s. In the same years the cytochrome P-450 dependent metabolism of vitamin E was characterized and a first series of studies on short-chain carboxyethyl metabolites in the 1990s paved the way to the hypothesis of a biological role for this metabolism alternative to vitamin E catabolism. In the last decade other physiological metabolites of vitamin E have been identified, such as α-tocopheryl phosphate and the long-chain metabolites formed by the ω-hydroxylase activity of cytochrome P-450. Recent findings are consistent with gene regulation and homeostatic roles of these metabolites in different experimental models, such as inflammatory, neuronal and hepatic cells, and in vivo in animal models of acute inflammation. Molecular mechanisms underlying these responses are under investigation in several laboratories and side-glances to research on other fat soluble vitamins may help to move faster in this direction. Other emerging aspects presented in this review paper include novel insights on the mechanisms of reduction of the cardiovascular risk, immunomodulation and antiallergic effects, neuroprotection properties in models of glutamate excitotoxicity and spino-cerebellar damage, hepatoprotection and prevention of liver toxicity by different causes and even therapeutic applications in non-alcoholic steatohepatitis. We here discuss these topics with the aim of stimulating the interest of the scientific community and further research activities that may help to celebrate this anniversary of vitamin E with an in-depth knowledge of its action as vitamin.

Assessment of Serum Nitrogen Species and Inflammatory Parameters in Relapsing-Remitting Multiple Sclerosis Patients Treated with Different Therapeutic Approaches

The role of nitric oxide and its reactive derivatives (NO _x ) is well known in the pathogenesis of multiple sclerosis, which is an inflammatory disease while NO _x seems to be important in coordinating inflammatory response. The purpose of the present study was to assess serum NO _x as one of the nitrogen species and inflammatory parameters in relapsing-remitting multiple sclerosis patients and to compare the effectiveness of various types of disease-modifying therapies that reduce nitric oxide and inflammatory biomarkers. Elevated NO _x level was observed in patients who received the first-line disease-modifying therapy (interferons beta-1a and beta-1b) in comparison with the subjects treated with the second-line disease-modifying therapy (natalizumab; fingolimod) and healthy controls without significant differences in C-reactive protein and interleukin-1 beta. A negative correlation was observed between serum NO _x level and the duration of multiple sclerosis confirmed in the whole study population and in subjects treated with the first-line agents. Only serum NO _x , concentration could reveal a potential efficacy of disease-modifying therapy with a better reduction in NO _x level due to the second-line agents of disease-modifying therapy.

Long-Term Vitamin E-Deficient Mice Exhibit Cognitive Dysfunction via Elevation of Brain Oxidation

Vitamin E inhibits oxidative processes in living tissues. We produced vitamin E-deficient mice by feeding them a vitamin E-deficient diet to verify the influence of chronic vitamin E deficiency on cognitive function. We measured cognitive function over a 5-d period using the Morris water maze task, as well as antioxidant enzyme activity and lipid peroxidation in discrete brain regions, and total serum cholesterol content. Three- and six-mo-old vitamin E-deficient and age-matched control mice were used. In addition, 24-mo-old mice were used as an aged-model. In the 3-mo-old mice, cognitive function in the vitamin E-deficient (short-term vitamin E-deficient) group was significantly impaired compared to age-matched controls. Although the lipid peroxidation products in the cerebral cortex, cerebellum and hippocampus did not significantly differ in 3-mo-old mice, the levels in the 6-mo-old vitamin E-deficient (long-term vitamin E-deficient) mice were significantly increased compared to age-matched controls. Serum cholesterol content was also significantly increased in the short- and long-term vitamin E-deficient mice compared to their respective age-matched controls. These results indicate that chronic vitamin E deficiency may slowly accelerate brain oxidation. Thus, vitamin E concentrations may need to be monitored in order to prevent the risk of cognitive dysfunction, even under normal conditions.

Impact of exogenous lipase supplementation on growth, intestinal function, mucosal immune and physical barrier, and related signaling molecules mRNA expression of young grass carp (Ctenopharyngodon idella)

This study investigated the effects of exogenous lipase supplementation on the growth performance, intestinal growth and function, immune response and physical barrier function, and related signaling molecules mRNA expression of young grass carp (Ctenopharyngodon idella). A total of 450 grass carp (255.02 ± 0.34 g) were fed five diets for 60 days. There were 5 dietary treatments that included a normal protein and lipid diet containing 30% crude protein (CP) with 5% ether extract (EE), and the low-protein and high-lipid diets (28% CP, 6% EE) supplemented with graded levels of exogenous lipase supplementation activity at 0, 1193, 2560 and 3730 U/kg diet. The results indicated that compared with a normal protein and lipid diet (30% CP, 5% EE), a low-protein and high-lipid diet (28% CP, 6% EE) (un-supplemented lipase) improved lysozyme activities and complement component 3 contents in the distal intestine (DI), interleukin 10 mRNA expression in the proximal intestine (PI), and glutathione S-transferases activity and glutathione content in the intestine of young grass carp. In addition, in low-protein and high-lipid diets, optimal exogenous lipase supplementation significantly increased acid phosphatase (ACP) activities and complement component 3 (C3) contents (P < 0.05), up-regulated the relative mRNA levels of antimicrobial peptides (liver expressed antimicrobial peptide 2 and hepcidin) and anti-inflammatory cytokines (interleukin 10 and transforming growth factor β1) and signaling molecules inhibitor protein-κBα (IκBα) and target of rapamycin (TOR) (P < 0.05), down-regulated the mRNA levels of pro-inflammatory cytokines (tumor necrosis factor α, interleukin 8, interferon γ2, and interleukin 1β), and signaling molecules (nuclear factor kappa B p65, IκB kinase β, IκB kinase γ) (P < 0.05) in the intestine of young grass carp. Moreover, optimal exogenous lipase supplementation significantly decreased reactive oxygen species (ROS), malondialdehyde (MDA) and protein carbonyl (PC) contents (P < 0.05), improved the activities of anti-superoxide anion (ASA) and anti-hydroxyl radical (AHR), glutathione content, and the activities and mRNA levels of antioxidant enzymes (copper/zinc superoxide dismutase, manganese superoxide dismutase, catalase, glutathione peroxidase, glutathione S-transferases and glutathione reductase) (P < 0.05), up-regulated signaling molecule NF-E2-related factor 2 (Nrf2) (P < 0.05), down-regulated signaling molecules (Kelch-like-ECH-associated protein 1a, Kelch-like-ECH-associated protein 1b) (P < 0.05) in the intestine of young grass carp. Furthermore, optimal exogenous lipase supplementation significantly elevated the mRNA levels of tight junction proteins (Occludin, zonula occludens 1, Claudin b, Claudin c and Claudin 3) (P < 0.05), down-regulated the mRNA levels of tight junction proteins (Claudin 12 and Claudin 15a) (P < 0.05), down-regulated signaling molecules myosin light chain kinase (P < 0.05) in the intestine of young grass carp. In conclusion, dietary lipid could partially spare protein, and the low-protein and high-lipid diet could improve growth, intestinal growth and function, immune response and antioxidant capability of fish. Meanwhile, in high-fat and low-protein diets, optimal exogenous lipase supplementation improved growth, intestinal growth and function, intestinal immunity, physical barrier, and regulated the mRNA expression of related signal molecules of fish. The optimal level of exogenous lipase supplementation in young grass carp (255-771 g) was estimated to be 1193 U kg(-1) diet.

Current Advances in the Biochemical and Physiological Aspects of the Treatment of Type 2 Diabetes Mellitus with Thiazolidinediones

The present review summarizes the current advances in the biochemical and physiological aspects in the treatment of type 2 diabetes mellitus (DM2) with thiazolidinediones (TZDs). DM2 is a metabolic disorder characterized by hyperglycemia, triggering the abnormal activation of physiological pathways such as glucose autooxidation, polyol's pathway, formation of advance glycation end (AGE) products, and glycolysis, leading to the overproduction of reactive oxygen species (ROS) and proinflammatory cytokines, which are responsible for the micro- and macrovascular complications of the disease. The treatment of DM2 has been directed toward the reduction of hyperglycemia using different drugs such as insulin sensitizers, as the case of TZDs, which are able to lower blood glucose levels and circulating triglycerides by binding to the nuclear peroxisome proliferator-activated receptor gamma (PPARγ) as full agonists. When TZDs interact with PPARγ, the receptor regulates the transcription of different genes involved in glucose homeostasis, insulin resistance, and adipogenesis. However, TZDs exhibit some adverse effects such as fluid retention, weight gain, hepatotoxicity, plasma-volume expansion, hemodilution, edema, bone fractures, and congestive heart failure, which limits their use in DM2 patients.