Tocopherols and tocotrienols plasma levels are associated with cognitive impairment

New insights into healthy ageing, inflammageing and frailty using metabolomics

Human ageing is a normal process and does not necessarily result in the development of frailty. A mix of genetic, environmental, dietary, and lifestyle factors can have an impact on ageing, and whether an individual develops frailty. Frailty is defined as the loss of physiological reserve both at the physical and cellular levels, where systemic processes such as oxidative stress and inflammation contribute to physical decline. The newest "omics" technology and systems biology discipline, metabolomics, enables thorough characterisation of small-molecule metabolites in biological systems at a particular time and condition. In a biological system, metabolites-cellular intermediate products of metabolic reactions-reflect the system's final response to genomic, transcriptomic, proteomic, epigenetic, or environmental alterations. As a relatively newer technique to characterise metabolites and biomarkers in ageing and illness, metabolomics has gained popularity and has a wide range of applications. We will give a comprehensive summary of what is currently known about metabolomics in studies of ageing, with a focus on biomarkers for frailty. Metabolites related to amino acids, lipids, carbohydrates, and redox metabolism may function as biomarkers of ageing and/or frailty development, based on data obtained from human studies. However, there is a complexity that underpins biological ageing, due to both genetic and environmental factors that play a role in orchestrating the ageing process. Therefore, there is a critical need to identify pathways that contribute to functional decline in people with frailty.

Embracing complexity of (brain) aging

Aging is a multifactorial process occurring in a pathophysiological continuum which leads to organ and system functional loss. While aging is not a disease, its pathophysiological continuum predisposes to illness and multimorbidity clusters which share common biomolecular mechanisms-the pillars of aging. Brain aging and neurodegeneration share many hallmarks with other age-related diseases. The central nervous system is often the weakest link susceptible to the aging process and its deterioration, resulting in cognitive impairment and other symptoms; the aging process is associated with proteostasis collapse, stem cell exhaustion, repair mechanisms, altered brain nutrient sensing, endothelial changes, inflammation, oxidative distress, and energy unbalance, as well as other disturbances. These mechanisms are highly interwoven, and considerable research is aimed at their disentanglement and detection of their clinically relevant impact, particularly in order to identify pharmacological and non-pharmacological preventive and therapeutic strategies.

Plasma lipidomics reveals potential lipid markers for the prediction of delayed neurocognitive recovery after cardiac surgery with cardiopulmonary bypass

BACKGROUND

Delayed neurocognitive recovery (DNR) is a cognitive change that affects patients after anesthesia and surgery, with a high incidence, severely impairing their quality of life. We identified relevant metabolic pathways to determine predictive lipid markers and understand the pathogenesis of DNR.

METHODS

A non-targeted lipidomic strategy using Waters Acquity I Class UPLC-Xevo G2-S QTOF UPLC-MS was employed to identify different lipids in the 24 h postoperative plasma of patients whose cognitive function was assessed 7-14 days after surgery. Principal component analysis, orthogonal partial least squares discriminant analysis, and receiver operating characteristic (ROC) curves were used to identify potential biomarkers for predicting DNR. Metabolic pathway analysis was performed using the online platform MetaboAnalyst 5.0.

RESULTS

Pre-operative hemoglobin was identified as an independent risk factor for DNR. The individual areas under the ROC curves (AUC) of the 5 representative lipids were all > 0.6, and the AUC of the combined predictor was 0.912. Glycerophospholipid metabolic pathway was dysregulated in patients with subsequent DNR.

CONCLUSION

This study identified a series of potential predictive biomarkers for DNR. These data suggested that glycerophospholipid metabolism may be the mechanism underlying the occurrence and progression of DNR.

Vitamin E and Its Molecular Effects in Experimental Models of Neurodegenerative Diseases

With the advancement of in vivo studies and clinical trials, the pathogenesis of neurodegenerative diseases has been better understood. However, gaps still need to be better elucidated, which justifies the publication of reviews that explore the mechanisms related to the development of these diseases. Studies show that vitamin E supplementation can protect neurons from the damage caused by oxidative stress, with a positive impact on the prevention and progression of neurodegenerative diseases. Thus, this review aims to summarize the scientific evidence of the effects of vitamin E supplementation on neuroprotection and on neurodegeneration markers in experimental models. A search for studies published between 2000 and 2023 was carried out in the PubMed, Web of Science, Virtual Health Library (BVS), and Embase databases, in which the effects of vitamin E in experimental models of neurodegeneration were investigated. A total of 5669 potentially eligible studies were identified. After excluding the duplicates, 5373 remained, of which 5253 were excluded after checking the titles, 90 articles after reading the abstracts, and 11 after fully reviewing the manuscripts, leaving 19 publications to be included in this review. Experiments with in vivo models of neurodegenerative diseases demonstrated that vitamin E supplementation significantly improved memory, cognition, learning, motor function, and brain markers associated with neuroregeneration and neuroprotection. Vitamin E supplementation reduced beta-amyloid (Aβ) deposition and toxicity in experimental models of Alzheimer's disease. In addition, it decreased tau-protein hyperphosphorylation and increased superoxide dismutase and brain-derived neurotrophic factor (BDNF) levels in rodents, which seems to indicate the potential use of vitamin E in preventing and delaying the progress of degenerative lesions in the central nervous system.

Gut Microbiota and its Metabolites: Bridge of Dietary Nutrients and Alzheimer's Disease

Alzheimer's disease (AD) is a neurodegenerative disease characterized by progressive cognitive impairment and neuroinflammation. Recent research has revealed the crucial role of gut microbiota and microbial metabolites in modulating AD. However, the mechanisms by which the microbiome and microbial metabolites affect brain function remain poorly understood. Here, we review the literature on changes in the diversity and composition of the gut microbiome in patients with AD and in animal models of AD. We also discuss the latest progress in understanding the pathways by which the gut microbiota and microbial metabolites from the host or diet regulate AD. By understanding the effects of dietary components on brain function, microbiota composition, and microbial metabolites, we examine the potential for manipulation of the gut microbiota through dietary intervention to delay the progression of AD. Although it is challenging to translate our understanding of microbiome-based approaches to dietary guidelines or clinical therapies, these findings provide an attractive target for promoting brain function.

Insights into prevention mechanisms of bioactive components from healthy diets against Alzheimer's disease

Alzheimer's disease (AD) is a progressive neurodegenerative disease in which senile plaques, neurofibrillary tangles, insulin resistance, oxidative stress, chronic neuroinflammation, and abnormal neurotransmission are the potential mechanisms involved in its onset and development. Although it is still an intractable disorder, diet intervention has been developed as an innovative strategy for AD prevention. Some bioactive compounds and micronutrients from food, including soy isoflavones, rutin, vitamin B1, etc., have exhibited numerous neuronal health-promoting effects in both in vivo and in vitro studies. It is well known that their antiapoptotic, antioxidative, and anti-inflammatory properties prevent the neuronal or glial cells from injury or death, minimize oxidative damage, inhibit the production of proinflammatory cytokines by modulating typical signaling pathways of MAPK, NF-kβ, and TLR, and further reduce Aβ genesis and tau hyperphosphorylation. However, parts of the dietary components trigger AD-related proteins productions and inflammasome as well as inflammatory gene upregulation. This review summarized the neuroprotective or nerve damage-promoting role and underlying molecular mechanisms of flavonoids, vitamins, and fatty acids via the data from library databases, PubMed, and journal websites, which provides a comprehensive analysis of the prevention potential of these dietary components against AD.

Low blood carotenoid status in dementia and mild cognitive impairment: A systematic review and meta-analysis

BACKGROUND

Given their potent antioxidation properties, carotenoids play a role in delaying and preventing dementia and mild cognitive impairment (MCI). However, observational studies have found inconsistent results regarding the associations between blood carotenoid levels and the risk of dementia and MCI. We conducted this systematic review and meta-analysis to investigate the relationship between blood carotenoid levels and the risk of dementia and MCI.

METHODS

A systematic search was performed in the Web of Science, PubMed, Embase, and Cochrane Library electronic databases to retrieve relevant English articles published from their inception until February 23, 2023. Study quality was assessed by the Newcastle-Ottawa scale. Standardized mean differences (SMDs) and 95% confidence intervals (CIs) were pooled using random-effect meta-analyses. Ultimately, 23 studies (n = 6610) involving 1422 patients with dementia, 435 patients with MCI, and 4753 controls were included.

RESULTS

Our meta-analysis showed that patients with dementia had lower blood lycopene (SMD: -0.521; 95%CI: -0.741, -0.301), α-carotene (SMD: -0.489; 95%CI: -0.697, -0.281), β-carotene (SMD: -0.476; 95%CI: -0.784, -0.168), lutein (SMD: -0.516; 95%CI: -0.753, -0.279), zeaxanthin (SMD: -0.571; 95%CI: -0.910, -0.232) and β-cryptoxanthin (SMD: -0.617; 95%CI: -0.953, -0.281) than the controls. Our results indicated that blood carotenoid levels were significantly lower in patients with dementia than in controls, despite high heterogeneity across the studies. Owing to insufficient data, we did not observe a similar and stable relationship between blood carotenoid levels and MCI.

CONCLUSIONS

Our meta-analysis indicated that lower blood carotenoid levels may be a risk factor for dementia and MCI.

Non-Enzymatic Antioxidants against Alzheimer's Disease: Prevention, Diagnosis and Therapy

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by progressive memory loss and cognitive decline. Although substantial research has been conducted to elucidate the complex pathophysiology of AD, the therapeutic approach still has limited efficacy in clinical practice. Oxidative stress (OS) has been established as an early driver of several age-related diseases, including neurodegeneration. In AD, increased levels of reactive oxygen species mediate neuronal lipid, protein, and nucleic acid peroxidation, mitochondrial dysfunction, synaptic damage, and inflammation. Thus, the identification of novel antioxidant molecules capable of detecting, preventing, and counteracting AD onset and progression is of the utmost importance. However, although several studies have been published, comprehensive and up-to-date overviews of the principal anti-AD agents harboring antioxidant properties remain scarce. In this narrative review, we summarize the role of vitamins, minerals, flavonoids, non-flavonoids, mitochondria-targeting molecules, organosulfur compounds, and carotenoids as non-enzymatic antioxidants with AD diagnostic, preventative, and therapeutic potential, thereby offering insights into the relationship between OS and neurodegeneration.

Suppression of Amyloid-β Adsorption on Endoplasmic Reticulum Stress-Mimicking Membranes by α-Tocopherol and α-Tocotrienol

Two forms of hydrophobic vitamin E (VE), α-tocopherol (Toc) and α-tocotrienol (Toc3), have been proposed to be effective against Alzheimer's disease (AD), the etiology of which is thought to involve endoplasmic reticulum (ER) stress. However, previous studies reported conflicting effects of Toc and Toc3 on the risk of AD. We prepared liposomes mimicking the phase separation of the ER membrane (solid-ordered/liquid-disordered phase separation) and studied how VE can influence the interaction between amyloid-β (Aβ) and the ER membrane. We found that Toc could inhibit the formation of the solid-ordered phase more significantly than Toc3. Furthermore, Aβ protofibril adsorption on ER stress-mimicking membranes was more strongly suppressed by Toc compared with Toc3. Therefore, we concluded that VE can relieve ER stress by destabilizing the solid-ordered phase of the ER membrane and subsequently reducing the amount of Aβ adsorbed on the membrane. Moreover, Toc exerted a stronger effect than Toc3.

Low Serum Vitamin D Status Is Associated with Incident Alzheimer's Dementia in the Oldest Old

Background. Vitamins A, D and E and beta-carotene may have a protective function for cognitive health, due to their antioxidant capacities. Methods. We analyzed data from 1334 non-demented participants (mean age 84 years) from the AgeCoDe study, a prospective multicenter-cohort of elderly general-practitioner patients in Germany, of whom n = 250 developed all-cause dementia and n = 209 developed Alzheimer’s dementia (AD) during 7 years of follow-up. We examined whether concentrations of vitamins A (retinol), D (25-hydroxycholecalciferol) and E (alpha-tocopherol) and beta-carotene, would be associated with incident (AD) dementia. Results. In our sample, 33.7% had optimum vitamin D concentrations (≥50 nmol/L). Higher concentrations of vitamin D were associated with lower incidence of all-cause dementia and AD (HR 0.99 (95%CI 0.98; 0.99); HR0.99 (95%CI 0.98; 0.99), respectively). In particular, subjects with vitamin D deficiency (25.3%, <25 nmol/L) were at increased risk for all-cause dementia and AD (HR1.91 (95%CI 1.30; 2.81); HR2.28 (95%CI 1.47; 3.53), respectively). Vitamins A and E and beta-carotene were unrelated to (AD) dementia. Conclusions. Vitamin D deficiency increased the risk to develop (AD) dementia. Our study supports the advice for monitoring vitamin D status in the elderly and vitamin D supplementation in those with vitamin D deficiency. We observed no relationships between the other vitamins with incident (AD) dementia, which is in line with previous observational studies.

Revisiting the therapeutic potential of tocotrienol

The therapeutic potential of the tocotrienol group stems from its nutraceutical properties as a dietary supplement. It is largely considered to be safe when consumed at low doses for attenuating pathophysiology as shown by animal models, in vitro assays, and ongoing human trials. Medical researchers and the allied sciences have experimented with tocotrienols for many decades, but its therapeutic potential was limited to adjuvant or concurrent treatment regimens. Recent studies have focused on targeted drug delivery by enhancing the bioavailability through carriers, self-sustained emulsions, nanoparticles, and ethosomes. Epigenetic modulation and computer remodeling are other means that will help increase chemosensitivity. This review will focus on the systemic intracellular anti-cancer, antioxidant, and anti-inflammatory mechanisms that are stimulated and/or regulated by tocotrienols while highlighting its potent therapeutic properties in a diverse group of clinical diseases.

Modeling the dynamics of energy imbalance: The free radical theory of aging and frailty revisited

The role of oxidative stress in aging and the newly conceptualized vision of frailty is of great interest for the possibility to define a framework able to explain the several modifications observed in all biological molecules along with age. In this review, the impact of oxidative stress is considered in aging processes as well as in frailty, the geriatric concept of declined capacity to cope with any stressor, leading to a status of reduced ability to maintain the homeostatic balance. Although some pharmacological and behavioral approaches have been proposed, we are still lacking efficacious management able to prevent and avoid frailty. This represents a fundamental challenge for future research in this field.

The Role of Vitamin E in Slowing Down Mild Cognitive Impairment: A Narrative Review

With the aging population, dementia emerges as a public health concern. In 2012, the Health and Retirement Study found that 8.8% of adults over 65 years suffered from dementia. The etiopathogenesis and treatment of dementia are not well understood. Antioxidant properties of Vitamin E and its major elements tocopherols and tocotrienols have been reported to be effective in slowing down the progression of dementia from its initial stage of Mild cognitive impairment (MCI). Therefore, the current review aims to explore the role of vitamin E on MCI. A literature search using the key words "Vitamin E, tocopherols, tocotrienols, and mild cognitive impairment" was conducted in MEDLINE (PubMed), CINAHL, and Google Scholar. The inclusion criteria were: (1) articles published in the past ten years; (2) published in English language; (3) published in peer-reviewed journals; and (4) descriptive and epidemiological or evaluation studies. Articles published prior to 2010, focused on other forms of dementia than MCI, grey literature and non-peer-reviewed articles were excluded. A total of 22 studies were included in the narrative synthesis. The results were equivocal. Eleven studies showed some level of the neuroprotective effect of Vitamin E, tocopherols and tocotrienols on the progression of MCI. The mixed results of this review suggest further exploration of the possible protective effects of Vitamin E on the development of dementia. Future studies can be conducted to decipher antioxidant properties of vitamin E and its association with slowing down the cognitive decline.

An Interactive Review on the Role of Tocotrienols in the Neurodegenerative Disorders

Neurodegenerative disorders, such as Parkinson's and Alzheimer's disease, are claimed to be of major concern causing a significant disease burden worldwide. Oxidative stress, mitochondrial dysfunction and nerve damage are the main reasons for the emergence of these diseases. The formation of reactive oxygen species (ROS) is the common chemical molecule that is formed from all these three interdependent mechanisms which is highly reactive toward the neuronal cells. For these reasons, the administration of tocotrienols (T3s), which is a potent antioxidant, is proven to cater to this problem, through in vitro and in vivo investigations. Interestingly, their therapeutic potentials are not only limited to antioxidant property but also to being able to reverse the neuronal damage and act as a shield for mitochondria dysfunction. Thereby, T3s prevents the damage to the neurons. In regards to this statement, in this review, we focused on summarizing and discussing the potential therapeutic role of T3s on Alzheimer's and Parkinson's diseases, and their protective mechanisms based on evidence from the in vitro and in vivo studies. However, there is no clinical trial conducted to prove the efficacy of T3s for Alzheimer's and Parkinson's subjects. As such, the therapeutic role of T3s for these neurodegenerative disorders is still under debate.

Decrypting the potential role of α-lipoic acid in Alzheimer's disease

Alzheimer's disease (AD) is one of the most prevalent neurodegenerative diseases with motor disturbances, cognitive decline, and behavioral impairment. It is characterized by the extracellular aggregation of amyloid-β plaques and the intracellular accumulation of tau protein. AD patients show a cognitive decline, which has been associated with oxidative stress, as well as mitochondrial dysfunction. Alpha-lipoic acid (α-LA), a natural antioxidant present in food and used as a dietary supplement, has been considered a promising agent for the prevention or treatment of neurodegenerative disorders. Despite multiple preclinical studies indicating beneficial effects of α-LA in memory functioning, and pointing to its neuroprotective effects, to date only a few studies have examined its effects in humans. Studies performed in animal models of memory loss associated with aging and AD have shown that α-LA improves memory in a variety of behavioral paradigms. Furthermore, molecular mechanisms underlying α-LA effects have also been investigated. Accordingly, α-LA shows antioxidant, antiapoptotic, anti-inflammatory, glioprotective, metal chelating properties in both in vivo and in vitro studies. In addition, it has been shown that α-LA reverses age-associated loss of neurotransmitters and their receptors. The review article aimed at summarizing and discussing the main studies investigating the neuroprotective effects of α-LA on cognition as well as its molecular effects, to improve the understanding of the therapeutic potential of α-LA in patients suffering from neurodegenerative disorders, supporting the development of clinical trials with α-LA.

The Associations of Plasma/Serum Carotenoids with Alzheimer's Disease: A Systematic Review and Meta-Analysis

BACKGROUND

Multiple lines of evidence indicate protective effects of carotenoids in Alzheimer's disease (AD). However, previous epidemiological studies reported inconsistent results regarding the associations between carotenoids levels and the risk of AD.

OBJECTIVE

Our study aims to evaluate the associations of six major members of carotenoids with the occurrence of AD by conducting a systematic review and meta-analysis.

METHODS

Following PRISMA guidelines, a comprehensive literature search of PubMed, Web of Science, Ebsco, and PsycINFO databases was conducted, and the quality of each included studies was evaluated by a validated scoring systems. Standardized mean differences (SMD) with 95% confidence intervals (CI) were determined by using a random effects model. Heterogeneity was evaluated by I2 statistics. Publication bias was detected using funnel plots and Egger's test.

RESULTS

Sixteen studies, with 10,633 participants were included. Pooled analysis showed significantly lower plasma/serum levels of lutein (SMD = -0.86, 95% CI: -1.67 to -0.05, p = 0.04) and zeaxanthin (SMD = -0.59; 95% CI: -1.12 to -0.06, p = 0.03) in patients with AD versus cognitively intact controls, while α-carotene (SMD = 0.21, 95% CI: -0.68 to 0.26, p = 0.39), β-carotene (SMD = 0.04, 95% CI: -0.57 to 0.65, p = 0.9), lycopene (SMD = -0.12, 95% CI: -0.96 to 0.72, p = 0.78), and β-cryptoxanthin (SMD = -0.09, 95% CI: -0.83 to 0.65, p = 0.81) did not achieve significant differences.

CONCLUSION

Of six major members of carotenoids, only lutein and zeaxanthin concentrations in plasma/serum were inversely related to the risk of AD. More high-quality longitudinal studies are needed to verify these findings.

Associations between vitamin E, oxidative stress markers, total homocysteine levels, and physical activity or cognitive capacity in older adults

This study examined the associations between vitamin E, oxidative stress markers, total homocysteine levels, and physical activity or cognitive capacity in older adults. One hundred and six older adults (62 men, 44 women) within the age range of 56-81 years participated. The Global Physical Activity Questionnaire and the Loewenstein Occupational Therapy Cognitive Assessment were used to assess physical activity and cognitive function, respectively. Vitamin E (e.g., α-tocopherol and γ-tocopherol), oxidative stress markers (e.g., total antioxidant capacity and nitric oxide), and total homocysteine were estimated. There were significant associations between physical activity (high versus moderate versus poor) and all biomarkers (all p = 0.000, and p = 0.010 for γ-tocopherol). While total homocysteine and total antioxidant capacity were significantly associated with cognitive capacity (p = 0.000), vitamin E levels (e.g., α-tocopherol and γ-tocopherol) and nitric oxide (p = 0.354, 0.103 and 0.060, respectively) were not related to cognitive capacity in older adults. This study concludes that physical activity was associated with Vitamin E, oxidative stress markers, total homocysteine, and cognitive capacity in older adults. Although cognitive capacity was associated with total homocysteine and total antioxidant capacity, it was unrelated to vitamin E levels and nitric oxide in older adults.

Tocopherols and Tocotrienols-Bioactive Dietary Compounds; What Is Certain, What Is Doubt?

Tocopherols and tocotrienols are natural compounds of plant origin, available in the nature. They are supplied in various amounts in a diet, mainly from vegetable oils, some oilseeds, and nuts. The main forms in the diet are α- and γ-tocopherol, due to the highest content in food products. Nevertheless, α-tocopherol is the main form of vitamin E with the highest tissue concentration. The α- forms of both tocopherols and tocotrienols are considered as the most metabolically active. Currently, research results indicate also a greater antioxidant potential of tocotrienols than tocopherols. Moreover, the biological role of vitamin E metabolites have received increasing interest. The aim of this review is to update the knowledge of tocopherol and tocotrienol bioactivity, with a particular focus on their bioavailability, distribution, and metabolism determinants in humans. Almost one hundred years after the start of research on α-tocopherol, its biological properties are still under investigation. For several decades, researchers' interest in the biological importance of other forms of vitamin E has also been growing. Some of the functions, for instance the antioxidant functions of α- and γ-tocopherols, have been confirmed in humans, while others, such as the relationship with metabolic disorders, are still under investigation. Some studies, which analyzed the biological role and mechanisms of tocopherols and tocotrienols over the past few years described new and even unexpected cellular and molecular properties that will be the subject of future research.

Low Serum Vitamin E Level Associated with Low Hand Grip Strength in Community-Dwelling Adults: Korean National Health and Nutrition Examination Survey (KNHANES VII) 2016-2018

This study assessed the association between serum vitamin E levels and hand grip strength (HGS) in community-dwelling adults data of 1011 men aged 50 years and older and 1144 postmenopausal women were analyzed. Low HGS was defined as HGS below the sex-stratified median value. Proportion of low HGS was the greatest in the lowest quintile of serum vitamin E level (<10.51 mg/L, 57.1%), with a decreasing trend toward the highest vitamin E quintile (>17.81 mg/L, 43.6%; p < 0.001). A one-unit (mg/L) decrease in vitamin E levels was associated with lower HGS in men (adjusted beta coefficient −0.10, 95% confidence interval [CI] −0.18 to −0.02, p = 0.019), but not in women (−0.01, 95% CI −0.06 to 0.03, p = 0.550). Compared with the middle quintile (Q3; 12.59–14.69 mg/L), the lowest vitamin E quintile (Q1) was associated with elevated odds of low HGS (adjusted odds ratio [aOR]: 1.38, p = 0.045), independent of sociodemographic factors, health-related lifestyles, comorbidities, dietary intake, and cholesterol level. However, the odds of low HGS did not differ significantly in other vitamin E quintiles (Q2, aOR 1.12; Q4, aOR 1.38; Q5, aOR 1.12; p > 0.05). Individuals with the lowest quintile vitamin E level had elevated odds of low HGS independent of covariates, findings which merit further validation.

Dynamic Interplay between Copper Toxicity and Mitochondrial Dysfunction in Alzheimer's Disease

Alzheimer's disease (AD) is a neurodegenerative disorder, affecting millions of people worldwide, a number expected to exponentially increase in the future since no effective treatments are available so far. AD is characterized by severe cognitive dysfunctions associated with neuronal loss and connection disruption, mainly occurring in specific brain areas such as the hippocampus, cerebral cortex, and amygdala, compromising memory, language, reasoning, and social behavior. Proteomics and redox proteomics are powerful techniques used to identify altered proteins and pathways in AD, providing relevant insights on cellular pathways altered in the disease and defining novel targets exploitable for drug development. Here, we review the main results achieved by both -omics techniques, focusing on the changes occurring in AD mitochondria under oxidative stress and upon copper exposure. Relevant information arises by the comparative analysis of these results, evidencing alterations of common mitochondrial proteins, metabolic cycles, and cascades. Our analysis leads to three shared mitochondrial proteins, playing key roles in metabolism, ATP generation, oxidative stress, and apoptosis. Their potential as targets for development of innovative AD treatments is thus suggested. Despite the relevant efforts, no effective drugs against AD have been reported so far; nonetheless, various compounds targeting mitochondria have been proposed and investigated, reporting promising results.

Vitamin E beyond Its Antioxidant Label

Vitamin E, comprising tocopherols and tocotrienols, is mainly known as an antioxidant. The aim of this review is to summarize the molecular mechanisms and signaling pathways linked to inflammation and malignancy modulated by its vitamers. Preclinical reports highlighted a myriad of cellular effects like modulating the synthesis of pro-inflammatory molecules and oxidative stress response, inhibiting the NF-κB pathway, regulating cell cycle, and apoptosis. Furthermore, animal-based models have shown that these molecules affect the activity of various enzymes and signaling pathways, such as MAPK, PI3K/Akt/mTOR, JAK/STAT, and NF-κB, acting as the underlying mechanisms of their reported anti-inflammatory, neuroprotective, and anti-cancer effects. In clinical settings, not all of these were proven, with reports varying considerably. Nonetheless, vitamin E was shown to improve redox and inflammatory status in healthy, diabetic, and metabolic syndrome subjects. The anti-cancer effects were inconsistent, with both pro- and anti-malignant being reported. Regarding its neuroprotective properties, several studies have shown protective effects suggesting vitamin E as a potential prevention and therapeutic (as adjuvant) tool. However, source and dosage greatly influence the observed effects, with bioavailability seemingly a key factor in obtaining the preferred outcome. We conclude that this group of molecules presents exciting potential for the prevention and treatment of diseases with an inflammatory, redox, or malignant component.

Palm Fruit Bioactive Complex (PFBc), a Source of Polyphenols, Demonstrates Potential Benefits for Inflammaging and Related Cognitive Function

Cognitive function is a key aspect of healthy aging. Inflammation associated with normal aging, also called inflammaging is a primary risk factor for cognitive decline. A diet high in fruits and vegetable and lower in calories, particularly a Mediterranean Diet, may lower the risk of age-related cognitive decline due in part to the associated high intake of antioxidants and polyphenols. A phenolic, Palm Fruit Bioactive complex (PFBc) derived from the extraction process of palm oil from oil palm fruit (Elaeis guineensis), is reported to offset inflammation due to its high antioxidant, especially vitamin E, and polyphenol content. The benefit is thought to be achieved via the influence of antioxidants on gene expression. It is the purpose of this comprehensive review to discuss the etiology, including gene expression, of mild cognitive impairment (MCI) specific to dietary intake of antioxidants and polyphenols and to focus on the potential impact of nutritional interventions specifically PFBc has on MCI. Several in vitro, in vivo and animal studies support multiple benefits of PFBc especially for improving cognitive function via anti-inflammatory and antioxidant mechanisms. While more human studies are needed, those completed thus far support the benefit of consuming PFBc to enhance cognitive function via its anti-inflammatory antioxidant functions.

The Impact of Nutrients on Mental Health and Well-Being: Insights From the Literature

A good nutritional status is important for maintaining normal body function and preventing or mitigating the dysfunction induced by internal or external factors. Nutritional deficiencies often result in impaired function, and, conversely, intakes at recommended levels can resume or further enhance body functions. An increasing number of studies are revealing that diet and nutrition are critical not only for physiology and body composition, but also have significant effects on mood and mental well-being. In particular, Western dietary habits have been the object of several research studies focusing on the relationship between nutrition and mental health. This review aims to summarize the current knowledge about the relationship between the intake of specific micro- and macronutrients, including eicosapentaenoic acid, docosahexaenoic acid, alpha-tocopherol, magnesium and folic acid, and mental health, with particular reference to their beneficial effect on stress, sleep disorders, anxiety, mild cognitive impairment, as well as on neuropsychiatric disorders, all significantly affecting the quality of life of an increasing number of people. Overall data support a positive role for the nutrients mentioned above in the preservation of normal brain function and mental well-being, also through the control of neuroinflammation, and encourage their integration in a well-balanced and varied diet, accompanied by a healthy lifestyle. This strategy is of particular importance when considering the global human aging and that the brain suffers significantly from the life-long impact of stress factors.

Health-Promoting Phytonutrients Are Higher in Grass-Fed Meat and Milk

While commission reports and nutritional guidelines raise concerns about the effects of consuming red meat on human health, the impacts of how livestock are raised and finished on consumer health are generally ignored. Meat and milk, irrespective of rearing practices, provide many essential nutrients including bioavailable protein, zinc, iron, selenium, calcium, and/or B12. Emerging data indicate that when livestock are eating a diverse array of plants on pasture, additional health-promoting phytonutrients—terpenoids, phenols, carotenoids, and anti-oxidants—become concentrated in their meat and milk. Several phytochemicals found in grass-fed meat and milk are in quantities comparable to those found in plant foods known to have anti-inflammatory, anti-carcinogenic, and cardioprotective effects. As meat and milk are often not considered as sources of phytochemicals, their presence has remained largely underappreciated in discussions of nutritional differences between feedlot-fed (grain-fed) and pasture-finished (grass-fed) meat and dairy, which have predominantly centered around the ω-3 fatty acids and conjugated linoleic acid. Grazing livestock on plant-species diverse pastures concentrates a wider variety and higher amounts of phytochemicals in meat and milk compared to grazing monoculture pastures, while phytochemicals are further reduced or absent in meat and milk of grain-fed animals. The co-evolution of plants and herbivores has led to plants/crops being more productive when grazed in accordance with agroecological principles. The increased phytochemical richness of productive vegetation has potential to improve the health of animals and upscale these nutrients to also benefit human health. Several studies have found increased anti-oxidant activity in meat and milk of grass-fed vs. grain-fed animals. Only a handful of studies have investigated the effects of grass-fed meat and dairy consumption on human health and show potential for anti-inflammatory effects and improved lipoprotein profiles. However, current knowledge does not allow for direct linking of livestock production practices to human health. Future research should systematically assess linkages between the phytochemical richness of livestock diets, the nutrient density of animal foods, and subsequent effects on human metabolic health. This is important given current societal concerns about red meat consumption and human health. Addressing this research gap will require greater collaborative efforts from the fields of agriculture and medicine.

Antioxidant action of vitamin E in vivo as assessed from its reaction products with multiple biological oxidants

Vitamin E acts as essential antioxidant against detrimental oxidation of biological molecules induced by multiple reactive species. To gain more insight into the physiological role of vitamin E, the levels of its oxidation products in humans under normal and pathological conditions were compared. α-Tocopherol quinone (α-TQ) and 5-nitro-γ-tocopherol (5-NgT) were focused. α-TQ is produced by multiple oxidants including oxygen radicals, peroxynitrite, hypochlorite, singlet oxygen, and ozone, while 5-NgT is produced by nitrogen dioxide radical derived from peroxynitrite and the reaction of nitrite and hypochlorite. The reported concentrations of α-TQ and 5-NgT in healthy human plasma are highly variable ranging from 15 to 360 and 4 to 170 nM, respectively. In general, the molar ratio 5-NgT/γ-tocopherol was higher than the ratio α-TQ/α-tocopherol. Both absolute concentrations of α-TQ and 5-NgT and the molar ratios to the parent tocopherols were elevated significantly in the plasma of patients with various diseases compared with healthy subjects except neurological diseases. The molar ratios of the products to the respective parent compounds decreased in the order of 5-NgT/γ-tocopherol > α-TQ/α-tocopherol > hydroxyoctadecadienoate/linoleate > 3-nitrotyrosine/tyrosine > isoprostane/arachidonate. The molar ratios of nitrated products to the respective parent compounds in human plasma are approximately 10^-2 for 5-NgT and 10^-5 for 3-nitrotyrosine, nitro-oleic acid, and 8-nitroguaine. These data indicate that vitamin E acts as an important physiological antioxidant and that α-TQ and 5-NgT represent biomarker for oxidative stress and nitrative stress respectively.

Role of nutraceuticals in cognition during aging and related disorders

Cognitive abilities are compromised with advancing age posing a great risk for the development of dementia and other related brain disorders. Genetic susceptibility as well as environmental exposures determine the fate of cognitive aging and its transition to pathological states. Emerging epidemiological and observational studies have revealed the importance of lifestyle factors including dietary patterns and nutritional intake in the maintenance of cognitive health and reducing the risk of neurodegenerative disorders. In this context, nutraceutical interventions have gained considerable attention in preventing age-related cognitive deficits and counteracting pathological processes. Nutraceuticals include dietary plants and derivatives, food supplements and processed foods with nutritional and pharmaceutical values. The present review highlights the importance of nutraceuticals in attenuating cognitive aging and its progression to dementia, with specific emphasis on chemical constituents, neurocognitive properties and mechanism of action.

Lipid Peroxidation and Antioxidant Supplementation in Neurodegenerative Diseases: A Review of Human Studies

Being characterized by progressive and severe damage in neuronal cells, neurodegenerative diseases (NDDs) are the major cause of disability and morbidity in the elderly, imposing a significant economic and social burden. As major components of the central nervous system, lipids play important roles in neural health and pathology. Disturbed lipid metabolism, particularly lipid peroxidation (LPO), is associated with the development of many NDDs, including Alzheimer’s disease (AD), Parkinson’s disease (PD), and amyotrophic lateral sclerosis (ALS), all of which show elevated levels of LPO products and LPO-modified proteins. Thus, the inhibition of neuronal oxidation might slow the progression and reduce the severity of NDD; natural antioxidants, such as polyphenols and antioxidant vitamins, seem to be the most promising agents. Here, we summarize current literature data that were derived from human studies on the effect of natural polyphenols and vitamins A, C, and E supplementation in patients with AD, PD, and ALS. Although these compounds may reduce the severity and slow the progression of NDD, research gaps remain in antioxidants supplementation in AD, PD, and ALS patients, which indicates that further human studies applying antioxidant supplementation in different forms of NDDs are urgently needed.

Vitamins in Alzheimer's Disease-Review of the Latest Reports

Alzheimer's disease (AD) is the most common form of dementia, and the aging of the population means that the number of cases is successively increasing. The cause of the disease has not been established, but it is suggested that many factors affect it, including nutritional aspects. As part of the work, the PubMed database has been searched, beginning from 2005, for terms related to key nutritional aspects. A diet rich in antioxidant vitamins can improve the cognitive functions of patients. Thanks to an adequate intake of B vitamins, homocysteine levels are reduced, which indirectly protects against the development of the disease. A properly balanced diet, as well as the use of appropriate supplementation, can contribute to improving the clinical condition of patients with AD.

Cognitive function improvement with astaxanthin and tocotrienol intake: a randomized, double-blind, placebo-controlled study

We examined the effects of the mixed ingestion of astaxanthin derived from Haematococcus pluvialis and tocotrienols on the cognitive function of healthy Japanese adults who feel a memory decline. Forty-four subjects were randomly but equally assigned to the astaxanthin-tocotrienols or placebo group. An astaxanthin-tocotrienols or placebo capsule was taken once daily before or after breakfast for a 12-week intervention period. The primary outcome was composite memory from the Cognitrax cognitive test, and the secondary outcomes were other cognitive functions and subjective symptoms for memory. Each group included 18 subjects in the efficacy analysis (astaxanthin-tocotrienols group, 55.4 ± 7.9 years; placebo group, 54.6 ± 6.9 years). The astaxanthin-tocotrienols group showed a significant improvement in composite memory and verbal memory in Cognitrax at Δ12 weeks compared with the placebo group. Additionally, the astaxanthin-tocotrienols group showed a significant improvement in the subjective symptom of "During the last week, have you had trouble remembering people's names or the names of things?" compared with the placebo group after 12 weeks. No adverse events were observed in this study. The results demonstrated that taking an astaxanthin-tocotrienols combination improves the composite memory and verbal memory of Japanese adults who feel a memory decline (UMIN 000031758).

Prevention of Cognitive Decline in Alzheimer's Disease by Novel Antioxidative Supplements

Oxidative stress plays a crucial role in Alzheimer’s disease (AD) from its prodromal stage of mild cognitive impairment. There is an interplay between oxidative stress and the amyloid β (Aβ) cascade via various mechanisms including mitochondrial dysfunction, lipid peroxidation, protein oxidation, glycoxidation, deoxyribonucleotide acid damage, altered antioxidant defense, impaired amyloid clearance, inflammation and chronic cerebral hypoperfusion. Based on findings that indicate that oxidative stress plays a major role in AD, oxidative stress has been considered as a therapeutic target of AD. In spite of favorable preclinical study outcomes, previous antioxidative components, including a single antioxidative supplement such as vitamin C, vitamin E or their mixtures, did not clearly show any therapeutic effect on cognitive decline in AD. However, novel antioxidative supplements can be beneficial for AD patients. In this review, we summarize the interplay between oxidative stress and the Aβ cascade, and introduce novel antioxidative supplements expected to prevent cognitive decline in AD.

Vitamin E and Alzheimer's disease: the mediating role of cellular aging

BACKGROUND

Vitamin E represents a potent antioxidant and anti-inflammatory system, playing a role in Alzheimer's disease (AD). Different plasma concentrations of the forms of vitamin E are observed in AD compared to cognitively healthy subjects.

AIM

Since these modifications may modulate the markers of oxidative stress and cellular aging, we aim to explore the relationship between vitamin E forms and leukocyte telomere length (LTL) in AD.

METHODS

53 AD subjects and 40 cognitively healthy controls (CTs) were enrolled. The vitamin E forms (α-, β-, γ- and δ-tocopherol, α-, β-, γ- and δ-tocotrienol), the ratio of α-tocopherylquinone/α-tocopherol and 5-nitro-γ-tocopherol/γ-tocopherol (markers of oxidative/nitrosative damage) and LTL were measured.

RESULTS AND DISCUSSION

Regression model was used to explore the associations of vitamin E forms and LTL with AD. The interaction of LTL in the association between vitamin E forms and AD was tested. AD subjects showed significantly lower concentrations of α-, β-, γ- and δ-tocopherol, α- and δ-tocotrienol, total tocopherols, total tocotrienols and total vitamin E compared to CTs. AD subjects showed higher values of nitrosative/oxidative damage. The adjusted analyses confirmed a significant relationship of AD with plasma concentrations of α- and β-tocopherols, δ-tocotrienol, total tocopherols, total tocotrienol, total vitamin E and oxidative/nitrosative damage. However, nitrosative damage was significantly associated with AD only in subjects with higher LTL and not in those expressing marked cellular aging.

CONCLUSIONS

Our study confirms the role of vitamin E in AD pathology and indicates that nitrosative damage influences the association with AD only in subjects characterized by longer LTL.

Potential Role of Tocotrienols on Non-Communicable Diseases: A Review of Current Evidence

Tocotrienol (T3) is a subfamily of vitamin E known for its wide array of medicinal properties. This review aimed to summarize the health benefits of T3, particularly in prevention or treatment of non-communicable diseases (NCDs), including cardiovascular, musculoskeletal, metabolic, gastric, and skin disorders, as well as cancers. Studies showed that T3 could prevent various NCDs, by suppressing 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR) in the mevalonate pathway, inflammatory response, oxidative stress, and alternating hormones. The efficacy of T3 in preventing/treating these NCDs is similar or greater compared to tocopherol (TF). TF may lower the efficacy of T3 because the efficacy of the combination of TF and T3 was lower than T3 alone in some studies. Data investigating the effects of T3 on osteoporosis, arthritis, and peptic ulcers in human are limited. The positive outcomes of T3 treatment obtained from the preclinical studies warrant further validation from clinical trials.

A Mixed Lipid Emulsion Containing Fish Oil and Its Effect on Electrophysiological Brain Maturation in Infants of Extremely Low Birth Weight: A Secondary Analysis of a Randomized Clinical Trial

OBJECTIVE

To assess whether parenteral nutrition for infants of extremely low birth weight using a mixed lipid emulsion that contains fish oil influences electrophysiological brain maturation.

STUDY DESIGN

The study is a prespecified secondary outcome analysis of a randomized controlled trial of 230 infants of extremely low birth weight receiving a mixed (soybean oil, medium-chain triglycerides, olive oil, and fish oil; intervention) or a soybean oil-based lipid emulsion (control). The study was conducted at a single-level IV neonatal care unit (Medical University Vienna; June 2012 to October 2015). Electrophysiological brain maturation (background activity, sleep-wake cycling, and brain maturational scores) was assessed biweekly by amplitude-integrated electroencephalography (birth to discharge).

RESULTS

A total of 317 amplitude-integrated electroencephalography measurements (intervention: n = 165; control: n = 152) from 121 (intervention: n = 63; control: n = 58) of 230 infants of the core study were available for analysis. Demographic characteristics were not significantly different. By 28 weeks of postmenstrual age, infants receiving the intervention displayed significantly greater percentages of continuous background activity. Total maturational scores and individual scores for continuity, cycling, and bandwidth were significantly greater. Maximum maturational scores were reached 2 weeks earlier in the intervention group (36.4 weeks, 35.4-37.5) compared with the control group (38.4 weeks, 37.1-42.4) (median, IQR; P < .001).

CONCLUSIONS

Using a mixed parenteral lipid emulsion that contains fish oil, we found that electrophysiological brain maturation was accelerated in infants who were preterm.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT01585935.

Vitamin E and Alzheimer's disease: what do we know so far?

Vitamin E has been proposed as a potential clinical intervention for Alzheimer's disease (AD) given the plausibility of its various biological functions in influencing the neurodegenerative processes associated with the condition. The tocopherol and tocotrienol isoforms of vitamin E have multiple properties including potent antioxidant and anti-inflammatory characteristics, in addition to influences on immune function, cellular signalling and lowering cholesterol. Several of these roles offer a theoretical rationale for providing benefit for the treatment of AD-associated pathology. Diminished circulating concentrations of vitamin E have been demonstrated in individuals with AD. Reduced plasma levels have furthermore been associated with an increased risk of AD development while intake, particularly from dietary sources, may limit or reduce the rate of disease progression. This benefit may be linked to synergistic actions between vitamin E isoforms and other micronutrients. Nevertheless, randomised trials have found limited and inconsistent evidence of vitamin E supplementation as an effective clinical intervention. Thus, despite a strong rationale in support of a beneficial role for vitamin E for the treatment of AD, the evidence remains inconclusive. Several factors may partly explain this discrepancy and represent the difficulties of translating complex laboratory evidence and dietary interactions into clinical interventions. Methodological design limitations of existing randomised trials and restrictions to supplementation with a single vitamin E isoform may also limit the influence of effect. Moreover, several factors influence individual responsiveness to vitamin E intake and recent findings suggest variation in the underlying genetic architecture attenuates vitamin E biological availability and activity which likely contributes to the variation in clinical responsiveness and the failure of randomised trials to date. Importantly, the clinical safety of vitamin E remains controversial and warrants further investigation.

Oxidative Stress in Neurodegenerative Diseases: From a Mitochondrial Point of View

Age is the main risk factor for a number of human diseases, including neurodegenerative disorders such as Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis, which increasing numbers of elderly individuals suffer. These pathological conditions are characterized by progressive loss of neuron cells, compromised motor or cognitive functions, and accumulation of abnormally aggregated proteins. Mitochondrial dysfunction is one of the main features of the aging process, particularly in organs requiring a high-energy source such as the heart, muscles, brain, or liver. Neurons rely almost exclusively on the mitochondria, which produce the energy required for most of the cellular processes, including synaptic plasticity and neurotransmitter synthesis. The brain is particularly vulnerable to oxidative stress and damage, because of its high oxygen consumption, low antioxidant defenses, and high content of polyunsaturated fats very prone to be oxidized. Thus, it is not surprising the importance of protecting systems, including antioxidant defenses, to maintain neuronal integrity and survival. Here, we review the role of mitochondrial oxidative stress in the aging process, with a specific focus on neurodegenerative diseases. Understanding the molecular mechanisms involving mitochondria and oxidative stress in the aging and neurodegeneration may help to identify new strategies for improving the health and extending lifespan.

Plasma Antioxidant Status in Patients with Alzheimer's Disease and Cognitively Intact Elderly: A Meta-Analysis of Case-Control Studies

Serum antioxidants may afford neuroprotection against Alzheimer's disease (AD) via correction of the pro-oxidative imbalance but findings reported have been inconsistent. We compared the pooled mean difference in serum levels of ten dietary antioxidants between patients with AD and cognitively intact controls from 52 studies in meta-analyses using random-effects models. Patients with AD had significantly lower plasma levels of α-carotene, β-carotene, lycopene, lutein, vitamin A, C, and E, and uric acid. No significant difference was observed for plasma levels of β-cryptoxanthin and zeaxanthin. Considerable heterogeneity was detected across studies. The lower serum levels of dietary antioxidants from the carotene and vitamin subclasses observed in individuals with AD suggest reduced systemic availability of these subclasses in this prevalent form of dementia. To our knowledge, these are the first meta-analyses to demonstrate lower serum lycopene and to evaluate β-cryptoxanthin, lutein, and zeaxanthin levels in AD. In light of the significant heterogeneity detected across studies, caution should be exercised in the interpretation of the data and therapeutic intervention approaches considered through supplementation measures. Our data may better inform interventions to improve antioxidant status in a condition of major public health importance.

Effects of vitamin E supplementation on the risk and progression of AD: a systematic review and meta-analysis

Objective: The association between vitamin E supplementation and Alzheimer's disease (AD) was controversial because of conflicting data in the literature. This study was designed to systematically evaluate evidence about the efficacy of vitamin E supplementation not only on the risk but also on the progression of AD. Design: Five electronic databases were searched for studies published up to June 2017. Articles reporting vitamin E supplementation and AD were included, and the random-effect model was performed for the meta-analysis about the relationship between vitamin E supplementation and AD. Results: Five cohort studies and three randomized controlled trial (RCT) studies (total n = 14,262) involving 1313 cases about vitamin E effects on the risk of AD and 244 cases about effects on progression of AD. The pooled RR for vitamin E supplemental and risk of AD was 0.81 [95% CI: 0.50-1.33, I ² = 69.2%]. Suitable data could not be extracted to do meta-analysis as there was no unified standard of outcome measure for studies on AD progression. We carefully analyzed and evaluated the authenticity and accuracy of every single trial, while reliable evidence could not be obtained. Conclusions: From what we do, neither the synthetic data on risk of AD nor the critical review on progression of AD could provide enough evidence on our research. Thus, we cannot draw a specific conclusion on the association or correlation between Vitamin E and AD.

Blood-based redox-signature and their association to the cognitive scores in MCI and Alzheimer's disease patients

Oxidative stress plays a pivotal and early role in the pathophysiology of Alzheimer's disease (AD). There is convincing evidence that oxidative alterations in AD and in mild cognitive impairment (MCI) patients are not limited to the brain but are extended to the blood compartment. However, the oxidative pattern in plasma is still inconclusive. Moreover, their potential association with the clinical scores MMSE (Mini-Mental State Examination) and MoCA (Montreal Cognitive Assessment) is poorly investigated. The aim of our study was to establish a pattern of blood-based redox alterations in prodromal AD and their evolution during the progression of the disease. Our results showed a reduction in the total antioxidant capacity (TAC) and an increase of the stress-response proteins apolipoprotein J (ApoJ) and Klotho in MCI subjects. For the first time, we evidenced circulating-proteasome activity. We found that the alteration of the circulating-proteasome activity is associated with the accumulation of oxidized proteins in plasma form early AD. Interestingly, the TAC, the levels of vitamin D and the activity of proteasome were positively associated to the clinical scores MMSE and MoCA. The levels of protein carbonyls and of ApoJ were negatively associated to the MMSE and MoCA scores. The levels of apolipoprotein D (ApoD) were not different between groups. Interestingly, the receiver operating characteristic (ROC) curves analysis indicated that these redox markers provide a fair classification of different groups with high accuracy. Overall, our results strengthen the notion that some specific oxidative markers could be considered as non-invasive blood-based biomarkers for an early MCI diagnosis and AD progression.

Anti-inflammatory Activity of Tocotrienols in Age-related Pathologies: A SASPected Involvement of Cellular Senescence

Tocotrienols (T3) have been shown to represent a very important part of the vitamin E family since they have opened new opportunities to prevent or treat a multitude of age-related chronic diseases. The beneficial effects of T3 include the amelioration of lipid profile, the promotion of Nrf2 mediated cytoprotective activity and the suppression of inflammation. All these effects may be the consequence of the ability of T3 to target multiple pathways. We here propose that these effects may be the result of a single target of T3, namely senescent cells. Indeed, T3 may act by a direct suppression of the senescence-associated secretory phenotype (SASP) produced by senescent cells, mediated by inhibition of NF-kB and mTOR, or may potentially remove the origin of the SASP trough senolysis (selective death of senescent cells). Further studies addressed to investigate the impact of T3 on cellular senescence “in vitro” as well as in experimental models of age-related diseases “in vivo” are clearly encouraged.

Neuroprotective Natural Molecules, From Food to Brain

The prevalence of neurodegenerative disorders is increasing; however, an effective neuroprotective treatment is still remaining. Nutrition plays an important role in neuroprotection as recently shown by epidemiological and biochemical studies which identified food components as promising therapeutic agents. Neuroprotection includes mechanisms such as activation of specific receptors, changes in enzymatic neuronal activity, and synthesis and secretion of different bioactive molecules. All these mechanisms are focused on preventing neuronal damage and alleviating the consequences of massive cell loss. Some neuropathological disorders selectively affect to particular neuronal populations, thus is important to know their neurochemical and anatomical properties in order to design effective therapies. Although the design of such treatments would be specific to neuronal groups sensible to damage, the effect would have an impact in the whole nervous system. The difficult overcoming of the blood brain barrier has hampered the development of efficient therapies for prevention or protection. This structure is a physical, enzymatic, and influx barrier that efficiently protects the brain from exogenous molecules. Therefore, the development of new strategies, like nanocarriers, that help to promote the access of neuroprotective molecules to the brain, is needed for providing more effective therapies for the disorders of the central nervous system (CNS). In order both to trace the success of these nanoplatforms on the release of the bioactive cargo in the CNS and determinate the concentration at trace levels of targets biomolecules by analytical chemistry and concretely separation instrumental techniques, constitute an essential tool. Currently, these techniques are used for the determination and identification of natural neuroprotective molecules in complex matrixes at different concentration levels. Separation techniques such as chromatography and capillary electrophoresis (CE), using optical and/or mass spectrometry (MS) detectors, provide multiples combinations for the quantitative and qualitative analysis at basal levels or higher concentrations of bioactive analytes in biological samples. Bearing this in mind, the development of food neuroprotective molecules as brain therapeutic agents is a complex task that requires the intimate collaboration and engagement of different disciplines for a successful outcome. In this sense, this work reviews the new advances achieved in the area toward a better understanding of the current state of the art and highlights promising approaches for brain neuroprotection.

Endogenous metabolites of vitamin E limit inflammation by targeting 5-lipoxygenase

Systemic vitamin E metabolites have been proposed as signaling molecules, but their physiological role is unknown. Here we show, by library screening of potential human vitamin E metabolites, that long-chain ω-carboxylates are potent allosteric inhibitors of 5-lipoxygenase, a key enzyme in the biosynthesis of chemoattractant and vasoactive leukotrienes. 13-((2R)-6-hydroxy-2,5,7,8-tetramethylchroman-2-yl)-2,6,10-trimethyltridecanoic acid (α-T-13'-COOH) can be synthesized from α-tocopherol in a human liver-on-chip, and is detected in human and mouse plasma at concentrations (8-49 nM) that inhibit 5-lipoxygenase in human leukocytes. α-T-13'-COOH accumulates in immune cells and inflamed murine exudates, selectively inhibits the biosynthesis of 5-lipoxygenase-derived lipid mediators in vitro and in vivo, and efficiently suppresses inflammation and bronchial hyper-reactivity in mouse models of peritonitis and asthma. Together, our data suggest that the immune regulatory and anti-inflammatory functions of α-tocopherol depend on its endogenous metabolite α-T-13'-COOH, potentially through inhibiting 5-lipoxygenase in immune cells.

Testing a Combination of Markers of Systemic Redox Status as a Possible Tool for the Diagnosis of Late Onset Alzheimer's Disease

Background

Blood-based parameters reflecting systemic abnormalities associated with typical brain physiopathological hallmarks could be a satisfactory answer to the need of less costly/intrusive and widely available biomarkers for late onset Alzheimer's disease (LOAD). Cumulating evidence from ourselves and others suggests that systemic oxidative stress (OxS) is precociously associated with LOAD. On this basis, we aimed to identify a combination of markers of redox status that could aid the diagnosis of LOAD.

Methods

We reexamined and crossed previous data on 9 serum markers of OxS obtained in a cohort including n = 84 controls and n = 90 LOAD patients by multivariate logistic regression analyses.

Results

A multimarker panel was identified that included significantly increased (hydroperoxides and uric acid) and decreased (thiols, residual antioxidant power, and arylesterase activity) markers. The multivariate model yielded an area under receiver-operating characteristic curve (AUC) of 0.808 for the discrimination between controls and LOAD patients, with specificity and sensitivity of 64% and 79%, respectively.

Conclusions

This study identified a panel of serum markers that distinguish individuals with LOAD from cognitively healthy control subjects. Replication studies on a larger independent cohort are required to confirm and extend our data.

Nutrition and Alzheimer Disease

We gathered some theoretic and practical concepts related to the importance of nutrition in the prevention and management of Alzheimer disease (AD). Besides the role of nutrients in brain development and functioning, some nutrients exert special control in the development of AD, due to their participation in neurotransmitter synthesis, their modulation in epigenetics mechanisms, and as antioxidants. In addition, some non-nutrient food-derived substances have shown potential in the control of neuroinflammation and consequently in the prevention of AD. Finally, it is important to be aware of the nutritional status and food intake patterns of the patient with AD.

A Review on the Relationship between Tocotrienol and Alzheimer Disease

Alzheimer&rsquo;s disease (AD) is plaguing the aging population worldwide due to its tremendous health care and socioeconomic burden. Current treatment of AD only offers symptomatic relief to patients. Development of agents targeting specific pathologies of AD is very slow. Tocotrienol, a member of the vitamin E family, can tackle many aspects of AD, such as oxidative stress, mitochondrial dysfunction and abnormal cholesterol synthesis. This review summarizes the current evidence on the role of tocotrienol as a neuroprotective agent. Preclinical studies showed that tocotrienol could reduce oxidative stress by acting as a free-radical scavenger and promoter of mitochondrial function and cellular repair. It also prevented glutamate-induced neurotoxicity in the cells. Human epidemiological studies showed a significant inverse relationship between tocotrienol levels and the occurrence of AD. However, there is no clinical trial to support the claim that tocotrienol can delay or prevent the onset of AD. As a conclusion, tocotrienol has the potential to be developed as an AD-preventing agent but further studies are required to validate its efficacy in humans.