Vitamin E for Alzheimer's dementia and mild cognitive impairment

Peripheral inflammation as a potential mechanism and preventive strategy for perioperative neurocognitive disorder under general anesthesia and surgery

General anesthesia, as a commonly used medical intervention, has been widely applied during surgical procedures to ensure rapid loss of consciousness and pain relief for patients. However, recent research suggests that general anesthesia may be associated with the occurrence of perioperative neurocognitive disorder (PND). PND is characterized by a decline in cognitive function after surgery, including impairments in attention, memory, learning, and executive functions. With the increasing trend of population aging, the burden of PND on patients and society's health and economy is becoming more evident. Currently, the clinical consensus tends to believe that peripheral inflammation is involved in the pathogenesis of PND, providing strong support for further investigating the mechanisms and prevention of PND.

Effects of vitamins and polyunsaturated fatty acids on cognitive function in older adults with mild cognitive impairment: a meta-analysis of randomized controlled trials

PURPOSE

Vitamins and polyunsaturated fatty acids (PUFAs) have been studied extensively as safe and manageable nutrient interventions for mild cognitive impairment (MCI). The purpose of the current meta-analysis was to examine the effects of vitamins and PUFAs on cognition and to compare the effects of single and multiple nutrient subgroups in patients with MCI.

METHODS

Randomized controlled trials (RCTs) written in English and Chinese were retrieved from eight databases, namely, PubMed, CENTRAL, Embase, CINAHL, Web of Science, SinoMed, CNKI, and Wanfang Data, from their respective dates of inception until 16 July 2023. The quality of the included studies was assessed using the Cochrane Risk of Bias Tool 2.0. Meta-analyses were performed to determine the standardized mean differences (SMDs) in global cognitive function, memory function, attention, visuospatial skills, executive function, and processing speed between the supplement and control groups using 95% confidence intervals (CI) and I2. Prospero registration number: CRD42021292360.

RESULTS

Sixteen RCTs that studied different types of vitamins and PUFAs were included. The meta-analysis revealed that vitamins affected global cognitive function (SMD = 0.58, 95% CI = [0.20, 0.96], P = 0.003), memory function (SMD = 2.55, 95% CI = [1.01, 4.09], P = 0.001), and attention (SMD = 3.14, 95% CI = [1.00, 5.28], P = 0.004) in patients with MCI, and PUFAs showed effects on memory function (SMD = 0.65, 95% CI = [0.32, 0.99], P < 0.001) and attention (SMD = 2.98, 95% CI = [2.11, 3.84], P < 0.001). Single vitamin B (folic acid [FA]: SMD = 1.21, 95% CI = [0.87, 1.55]) supplementation may be more effective than multiple nutrients (FA and vitamin B12: SMD = 0.71, 95% CI = [0.41, 1.01]; and FA combined with docosahexaenoic acid [DHA]: SMD = 0.58, 95% CI = [0.34, 0.83]) in global cognitive function.

CONCLUSIONS

FA, vitamin B6, vitamin B12, and vitamin D may improve global cognitive function, memory function, and attention in patients with MCI. Eicosapentaenoic acid (EPA) and DHA may improve memory function and attention. We also noted that FA may exert a greater effect than a vitamin B combination (FA and vitamin B12) or the combination of FA and DHA. However, because of the low evidence-based intensity, further trials are necessary to confirm these findings.

Ferroptosis: A new strategy for targeting Alzheimer's disease

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by a complex pathogenesis, which involves the formation of amyloid plaques and neurofibrillary tangles. Many recent studies have revealed a close association between ferroptosis and the pathogenesis of AD. Factors such as ferroptosis-associated iron overload, lipid peroxidation, disturbances in redox homeostasis, and accumulation of reactive oxygen species have been found to contribute to the pathological progression of AD. In this review, we explore the mechanisms underlying ferroptosis, describe the link between ferroptosis and AD, and examine the reported efficacy of ferroptosis inhibitors in treating AD. Finally, we discuss the potential challenges to ferroptosis inhibitors use in the clinic, enabling their faster use in clinical treatment.

A Review of the Current Status of Disease-Modifying Therapies and Prevention of Alzheimer's Disease

Alzheimer's disease is the most common form of dementia and includes cognitive, personality, and behavioral changes. The 2024 report from the Alzheimer's Association estimated that 6.9 million adults >65 years in the US are currently living with Alzheimer's disease. Modeling studies predict that this number will double by 2050, and associated healthcare costs will reach $1 trillion. In June 2021, regulatory approval of aducanumab, a humanized recombinant monoclonal antibody to amyloid ß, initially raised expectations for improved disease-modifying therapy. However, in February 2024, production of aducanumab and a post-marketing clinical trial ceased in the US due to the costs and limitations of aducanumab therapy. In March 2024, biobank data identified significant modifiable risk factors for Alzheimer's disease, including diabetes mellitus, exposure to nitrogen dioxide (a proxy for air pollution), and the frequency of alcohol intake. Therefore, modification of identifiable risk factors, combined with testing for disease-susceptibility genes, could be the most effective approach to reduce the incidence. This article aims to review the current status of disease-modifying therapies and prevention of Alzheimer's disease.

Alzheimer's Disease Puzzle: Delving into Pathogenesis Hypotheses

Alzheimer's disease (AD) is a prevalent neurodegenerative disease characterized by both amnestic and non-amnestic clinical manifestations. It accounts for approximately 60-70% of all dementia cases worldwide. With the increasing number of AD patients, elucidating underlying mechanisms and developing corresponding interventional strategies are necessary. Hypotheses about AD such as amyloid cascade, Tau hyper-phosphorylation, neuroinflammation, oxidative stress, mitochondrial dysfunction, cholinergic, and vascular hypotheses are not mutually exclusive, and all of them play a certain role in the development of AD. The amyloid cascade hypothesis is currently the most widely studied; however, other hypotheses are also gaining support. This article summarizes the recent evidence regarding major pathological hypotheses of AD and their potential interplay, as well as the strengths and weaknesses of each hypothesis and their implications for the development of effective treatments. This could stimulate further studies and promote the development of more effective therapeutic strategies for AD.

The Latest Advances in the Diagnosis and Treatment of Dementia

Dementia is a debilitating neurological condition that is characterized by persistent cognitive decline. It is a global health challenge, with a rapidly increasing prevalence due to an increasing aging population. Although definitive diagnosis of various conditions of dementia is only possible by autopsy, clinical diagnosis can be performed by a specialist. The diagnostic process has evolved with recent breakthroughs in diagnostic tools, such as advanced imaging techniques and biomarkers. These tools facilitate early and accurate identification of the condition. Early diagnosis is vital, as it enables timely interventions to improve the quality of life for affected individuals. Treatment strategies for dementia encompass both pharmacological and non-pharmacological approaches. Non-pharmacological treatments include cognitive training and lifestyle modifications. Among pharmacological treatments, acetyl-cholinesterase inhibitors including donepezil, rivastigmine, and galantamine can be used in various doses based on the severity of the disease. Apart from these, N-methyl-D-aspartate receptor antagonists such as memantine can also be used. Furthermore, personalized treatments have also gained significant attention in dementia treatment. Interdisciplinary care, involving healthcare professionals, social workers, and support networks, is crucial for comprehensive and holistic dementia management.

Evaluation and treatment approaches for neurological post-acute sequelae of COVID-19: A consensus statement and scoping review from the global COVID-19 neuro research coalition

Post-acute neurological sequelae of COVID-19 affect millions of people worldwide, yet little data is available to guide treatment strategies for the most common symptoms. We conducted a scoping review of PubMed/Medline from 1/1/2020-4/1/2023 to identify studies addressing diagnosis and treatment of the most common post-acute neurological sequelae of COVID-19 including: cognitive impairment, sleep disorders, headache, dizziness/lightheadedness, fatigue, weakness, numbness/pain, anxiety, depression and post-traumatic stress disorder. Utilizing the available literature and international disease-specific society guidelines, we constructed symptom-based differential diagnoses, evaluation and management paradigms. This pragmatic, evidence-based consensus document may serve as a guide for a holistic approach to post-COVID neurological care and will complement future clinical trials by outlining best practices in the evaluation and treatment of post-acute neurological signs/symptoms.

Association of Fruit and Vegetable Consumption With Mild Cognitive Impairment in Low- and Middle-Income Countries

BACKGROUND

Inadequate fruit and vegetable intake may be associated with cognitive decline but its association with mild cognitive impairment (MCI; a preclinical stage of dementia) is largely unknown. Therefore, we examined the association of fruit and vegetable consumption with MCI among middle-aged and older adults from low- and middle-income countries (LMICs).

METHODS

Cross-sectional, nationally representative data from the WHO Study on global AGEing and adult health were analyzed. MCI was defined using the National Institute on Aging-Alzheimer's Association criteria. Quintiles of vegetable and fruit consumption were created based on the number of servings consumed on a typical day. Multivariable logistic regression analysis was conducted.

RESULTS

Data on 32 715 individuals aged ≥50 years were analyzed (mean [standard deviation] age 62.1 [15.6] years; 51.7% females). Greater fruit consumption was dose-dependently associated with lower odds for MCI. For example, the highest quintile (vs lowest) had 47% lower odds for MCI (odds ratio [OR] = 0.53; 95% confidence interval [CI] = 0.43-0.66). For vegetable consumption, compared to the lowest quintile, the second to fourth quintiles had significant 38%-44% lower odds for MCI but there was no significant difference for the highest quintile (OR = 0.82; 95% CI = 0.59-1.15).

CONCLUSIONS

Higher fruit and vegetable consumption was associated with lower odds for MCI among middle-aged and older adults from LMICs, but no significant differences were found between the highest and lowest quintiles of vegetable consumption. Future longitudinal studies are required to explore these findings in more depth, and mechanistic studies are required to elucidate on the observed possible U-shaped association between vegetable consumption and MCI.

Mechanisms of ferroptosis in Alzheimer's disease and therapeutic effects of natural plant products: A review

Neurodegenerative diseases, such as Alzheimer's disease (AD), are characterized by massive loss of specific neurons. It is a progressive disabling, severe and fatal complex disease. Due to its complex pathogenesis and limitations of clinical treatment strategies, it poses a serious medical challenge and medical burden worldwide. The pathogenesis of AD is not clear, and its potential biological mechanisms include aggregation of soluble amyloid to form insoluble amyloid plaques, abnormal phosphorylation of tau protein and formation of intracellular neurofibrillary tangles (NFT), neuroinflammation, ferroptosis, oxidative stress and metal ion disorders. Among them, ferroptosis is a newly discovered programmed cell death induced by iron-dependent lipid peroxidation and reactive oxygen species. Recent studies have shown that ferroptosis is closely related to AD, but the mechanism remains unclear. It may be induced by iron metabolism, amino acid metabolism and lipid metabolism affecting the accumulation of iron ions. Some iron chelating agents (deferoxamine, deferiprone), chloroiodohydroxyquine and its derivatives, antioxidants (vitamin E, lipoic acid, selenium), chloroiodohydroxyquine and its derivatives Fer-1, tet, etc. have been shown in animal studies to be effective in AD and exert neuroprotective effects. This review summarizes the mechanism of ferroptosis in AD and the regulation of natural plant products on ferroptosis in AD, in order to provide reference information for future research on the development of ferroptosis inhibitors.

Non-linear relationship between dietary vitamin E intake and cognitive performance in older adults

OBJECTIVES

This study aimed to explore the relationship between dietary vitamin E (VE) intake and cognitive function in older adults.

STUDY DESIGN

This was a cross-sectional study.

METHODS

We applied data from the National Health and Nutrition Examination Survey obtained during 2011-2014 that met our requirements. The cognitive ability assessments included the Consortium to Establish a Registry for Alzheimer's Disease Word Learning (CERAD-WL) and Delayed Recall (CERAD-DR) tests, the animal fluency test, the Digit Symbol Substitution Test, and a composite z-score calculated by summing z-scores of individual tests. We used binary logistic regression analysis to explore the relationship between VE intake and cognitive performance. The results are reported using odds ratios and 95% confidence intervals. Our study also included sex-stratified analyses and sensitivity analysis. A restricted cubic splines model was used to evaluate the dose-response relationship between dietary VE intake and cognitive function.

RESULTS

This study found that a higher intake of dietary VE was associated with a lower risk of cognitive impairment in patients. Sensitivity analysis shows stable results. The results of the gender stratification analysis showed that dietary VE intake was negatively related to the risk of cognitive disorder among females. An irregular L-shaped dose-response relationship was observed between dietary VE intake and cognitive impairment risk.

CONCLUSIONS

Dietary VE intake was negatively related to the risk of cognitive disorder in older adults, with a higher VE intake lowering the risk.

Low dietary vitamin E intake is associated with high risk of incident dementia among older adults: The Shanghai Aging Study

Background

Growing evidence has shown the association between vitamin E intake and the risk of cognitive decline, but the conclusions were inconsistent. This study aimed to verify the hypothesis that vitamin E intake is associated with incident dementia and deterioration of global cognition.

Materials and methods

We followed 1,550 non-demented community residents aged ≥60 years for an average of 5.2 years in the Shanghai Aging Study. Baseline vitamin E intake were measured by the Food Frequency Questionnaire. Cognitive function was evaluated by a battery of neuropsychological tests. Consensus diagnosis of incident dementia was made based on the DSM-IV criteria.

Results

During the follow-up, 135 cases (8.7%) of incident dementia were identified. The incidence rates of dementia in low, low-medium, medium-high, and high vitamin E intake groups were 2.8, 1.5, 1.6, and 0.7 per 100 person-years, respectively (P < 0.001). Participants with low vitamin E intake had a significantly higher risk of incident dementia than those with higher intake [compared with the highest intake group: hazard ratio (HR) 2.34, 95% confidence interval (CI) 1.20-4.57] after adjusting for confounders. Vitamin E intake was negatively correlated to the rate of annual decline of Mini-Mental State Examination score with the adjustment of confounders (β = 0.019, p = 0.001).

Conclusion

Vitamin E intake is negatively correlated with the risk of dementia in older adults. An appropriate high amount of vitamin E intake from the diet might be helpful to prevent future cognitive decline.

Astrocytes as a Therapeutic Target in Alzheimer's Disease-Comprehensive Review and Recent Developments

Alzheimer's disease (AD) is a frequent and disabling neurodegenerative disorder, in which astrocytes participate in several pathophysiological processes including neuroinflammation, excitotoxicity, oxidative stress and lipid metabolism (along with a critical role in apolipoprotein E function). Current evidence shows that astrocytes have both neuroprotective and neurotoxic effects depending on the disease stage and microenvironmental factors. Furthermore, astrocytes appear to be affected by the presence of amyloid-beta (Aβ), with alterations in calcium levels, gliotransmission and proinflammatory activity via RAGE-NF-κB pathway. In addition, astrocytes play an important role in the metabolism of tau and clearance of Aβ through the glymphatic system. In this review, we will discuss novel pharmacological and non-pharmacological treatments focused on astrocytes as therapeutic targets for AD. These interventions include effects on anti-inflammatory/antioxidant systems, glutamate activity, lipid metabolism, neurovascular coupling and glymphatic system, calcium dysregulation, and in the release of peptides which affects glial and neuronal function. According to the AD stage, these therapies may be of benefit in either preventing or delaying the progression of the disease.

Insight into the potential role of ferroptosis in neurodegenerative diseases

Ferroptosis is a newly discovered way of programmed cell death, mainly caused by the accumulation of iron-dependent lipid peroxides in cells, which is morphologically, biochemically and genetically different from the previously reported apoptosis, necrosis and autophagy. Studies have found that ferroptosis plays a key role in the occurrence and development of neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease and vascular dementia, which suggest that ferroptosis may be involved in regulating the progression of neurodegenerative diseases. At present, on the underlying mechanism of ferroptosis in neurodegenerative diseases is still unclear, and relevant research is urgently needed to clarify the regulatory mechanism and provide the possibility for the development of agents targeting ferroptosis. This review focused on the regulatory mechanism of ferroptosis and its various effects in neurodegenerative diseases, in order to provide reference for the research on ferroptosis in neurodegenerative diseases.

Association of vitamin E intake in diet and supplements with risk of dementia: A meta-analysis

Background

Dementia is a chronic progressive neurodegenerative disease that can lead to disability and death in humans, but there is still no effective prevention and treatment. Due to the neuroprotective effects of vitamin E, a large number of researchers have explored whether vitamin E can reduce the risk of dementia. Some researchers believe that vitamin E can reduce the risk of dementia, while others hold the opposite conclusion. We therefore performed a meta-analysis to clarify the relationship between them.

Methods

We searched PubMed, Embase, and Web of Science databases for articles on the connection of dietary and supplementation vitamin E with dementia risk from inception through April 2022 using the main keywords “dementia,” “Alzheimer's disease,” “vitamin E,” and “tocopherol,” and used a random-utility model for pooled effect sizes. Odds ratios (OR) and 95% confidence intervals were derived using lower and higher doses as contrasts. Obtained data were shown and assessed using Stata12.0 free software.

Results

We included 15 articles in sum. Among them, there were nine articles containing AD. By comparing the highest intake with the lowest intake, Combined ORs for high intake were as follows: dementia (OR = 0.79, 95% CI 0.70–0.88 I² = 35.0%), Alzheimer's disease (OR = 0.78, 95% CI 0.64–0.94 I² = 36.9%). Subgroup analyses were also performed by study type, diet and supplementation, and NOS score.

Conclusions

High vitamin E intake from diet and supplements significantly reduces the risk of dementia and Alzheimer's disease.

Amylin and Secretases in the Pathology and Treatment of Alzheimer's Disease

Alzheimer’s disease remains a prevailing neurodegenerative condition which has an array physical, emotional, and financial consequences to patients and society. In the past decade, there has been a greater degree of investigation on therapeutic small peptides. This group of biomolecules have a profile of fundamentally sound characteristics which make them an intriguing area for drug development. Among these biomolecules, there are four modulatory mechanisms of interest in this review: alpha-, beta-, gamma-secretases, and amylin. These protease-based biomolecules all have a contributory role in the amyloid cascade hypothesis. Moreover, the involvement of various biochemical pathways intertwines these peptides to have shared regulators (i.e., retinoids). Further clinical and translational investigation must occur to gain a greater understanding of its potential application in patient care. The aim of this narrative review is to evaluate the contemporary literature on these protease biomolecule modulators and determine its utility in the treatment of Alzheimer’s disease.

Survey Results of Speech-Language Pathologists Working With Cognitive-Communication Disorders: Improving Practices for Mild Cognitive Impairment and Early-Stage Dementia From Alzheimer's Disease

PURPOSE

As the incidence of Alzheimer's disease (AD) continues to rise, there is a need for interventions that focus on risk reduction and early disease management. Speech-language pathologists (SLPs) can contribute to risk reduction efforts and deliver cognitive interventions; however, the nature and frequency of current clinical practice in those areas is unclear. Therefore, the purpose of this study was to conduct an exploratory survey of the cognitive-communication practices and needs of SLPs for adults with mild cognitive impairment (MCI) and early-stage dementia from AD, to inform future research and clinical training efforts.

METHOD

SLPs completed an online survey that assessed five areas of practice specific to cognitive-communication and MCI and early-stage dementia: (a) education and training, (b) MCI subtype knowledge and consideration, (c) goals and treatment practices, (d) assessment of everyday living skills, and (e) general clinical practices and needs.

RESULTS

One hundred fifty-seven SLPs completed the survey and represented a range of practice experience. Results revealed a discrepancy between the number of SLPs who provide services to adults with MCI or early-stage dementia and those who have received formal training to do so, suggesting a reliance on clinical practice experience. Participants primarily reported using interview and informal methods to assess daily activities and often described using compensatory-based treatments.

CONCLUSIONS

These findings contribute to the limited knowledge about SLPs' cognitive-communication practices to help improve early-disease management for AD, a rapidly growing population in need of SLPs' services. More research is needed to support SLPs in being maximally effective when working with clients early in the AD continuum.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.19787728.

Iron Dyshomeostasis and Ferroptosis: A New Alzheimer’s Disease Hypothesis?

Iron plays a crucial role in many physiological processes of the human body, but iron is continuously deposited in the brain as we age. Early studies found iron overload is directly proportional to cognitive decline in Alzheimer’s disease (AD). Amyloid precursor protein (APP) and tau protein, both of which are related to the AD pathogenesis, are associated with brain iron metabolism. A variety of iron metabolism-related proteins have been found to be abnormally expressed in the brains of AD patients and mouse models, resulting in iron deposition and promoting AD progression. Amyloid β (Aβ) and hyperphosphorylated tau, two pathological hallmarks of AD, can also promote iron deposition in the brain, forming a vicious cycle of AD development-iron deposition. Iron deposition and the subsequent ferroptosis has been found to be a potential mechanism underlying neuronal loss in many neurodegenerative diseases. Iron chelators, antioxidants and hepcidin were found useful for treating AD, which represents an important direction for AD treatment research and drug development in the future. The review explored the deep connection between iron dysregulation and AD pathogenesis, discussed the potential of new hypothesis related to iron dyshomeostasis and ferroptosis, and summarized the therapeutics capable of targeting iron, with the expectation to draw more attention of iron dysregulation and corresponding drug development.

Alzheimer's Disease: Pathogenesis and Therapeutic Interventions

BACKGROUND

Alzheimer's Disease (AD) is the most common cause of dementia. Genetics, excessive exposure to environmental pollutants, as well as unhealthy lifestyle practices are often linked to the development of AD. No therapeutic approach has achieved complete success in treating AD; however, early detection and management with appropriate drugs are key to improving prognosis.

INTERVENTIONS

The pathogenesis of AD was extensively discussed in order to understand the reasons for the interventions suggested. The interventions reviewed include the use of different therapeutic agents and approaches, gene therapy, adherence to healthy dietary plans (Mediterranean diet, Okinawan diet and MIND diet), as well as the use of medicinal plants. The potential of nanotechnology as a multidisciplinary and interdisciplinary approach in the design of nano-formulations of AD drugs and the use of Superparamagnetic Iron Oxide Nanoparticles (SPIONs) as theranostic tools for early detection of Alzheimer's disease were also discussed.

Walnut intake, cognitive outcomes and risk factors: a systematic review and meta-analysis

BACKGROUND

Walnuts contain nutrients that are associated with improved cognitive health. To our knowledge, no review has systematically examined the effects of walnuts on cognitive function and risk for cognitive decline.

OBJECTIVE

To conduct a systematic review and meta-analysis evaluating the effects of walnut intake on cognition-related outcomes and risk-factors for cognitive decline in adults.

METHODS

Medline®, Commonwealth Agricultural Bureau, and Cochrane Central Register of Controlled Trials were searched for randomized controlled trials (RCTs) and observational studies published until April 2020 on walnut intake, cognition (e.g. cognitive function, stroke, and mood), and selected risk factors for cognitive decline (e.g. glucose homeostasis and inflammation). Risk-of-bias and strength-of-evidence assessments were conducted using standard validated tools. Random-effects meta-analyses were conducted when ≥3 studies reported quantitative data for each outcome.

RESULTS

32 RCT and 7 observational study publications were included. Meta-analysis of cognition-related outcomes could not be conducted due to heterogeneity of tests. None of the 5 cognition RCTs found significant effects of walnuts on overall cognition, although 3 studies found improvements on subdomains and/or subgroups. All 7 observational studies found significant associations and a dose-response relationship between walnut intake and cognition-related outcomes. Meta-analyses of 27 RCTs reporting glucose homeostasis and inflammation outcomes, selected risk factors for cognitive decline, did not show significant effects of walnut intake.

CONCLUSIONS

Due to the non-uniformity of tests for cognition-related outcomes, definitive conclusions regarding the effect of walnut consumption on cognition could not be reached. Additionally, evidence does not show associations between walnut intake and glucose homeostasis or inflammation, cognitive decline risk-factors. High-quality studies with standardized measures are needed to clarify the role of walnuts in cognitive health.KEY MESSAGESThis is a systematic review and meta-analysis of 5 randomized clinical trials and 7 observational study articles of the impact of walnut intake on cognition decline and 27 randomized clinical trials of the effect of walnut intake on risk factors for cognitive decline including glucose homeostasis and inflammation.The non-uniformity of tests performed to measure cognitive function in the various studies did not allow for a meta-analysis of these studies. A definitive conclusion could therefore not be reached regarding the effect of walnut intake on cognitive decline.The evidence available does not show an association between walnut intake and glucose homeostasis or inflammation.

Insulin and α-Tocopherol Enhance the Protective Effect of Each Other on Brain Cortical Neurons under Oxidative Stress Conditions and in Rat Two-Vessel Forebrain Ischemia/Reperfusion Injury

Clinical trials show that insulin administered intranasally is a promising drug to treat neurodegenerative diseases, but at high doses its use may result in cerebral insulin resistance. Identifying compounds which could enhance the protective effects of insulin, may be helpful to reduce its effective dose. Our aim was thus to study the efficiency of combined use of insulin and α-tocopherol (α-T) to increase the viability of cultured cortical neurons under oxidative stress conditions and to normalize the metabolic disturbances caused by free radical reaction activation in brain cortex of rats with two-vessel forebrain ischemia/reperfusion injury. Immunoblotting, flow cytometry, colorimetric, and fluorometric techniques were used. α-T enhanced the protective and antioxidative effects of insulin on neurons in oxidative stress, their effects were additive. At the late stages of oxidative stress, the combined action of insulin and α-T increased Akt-kinase activity, inactivated GSK-3beta and normalized ERK1/2 activity in cortical neurons, it was more effective than either drug action. In the brain cortex, ischemia/reperfusion increased the lipid peroxidation product content and caused Na⁺,K⁺-ATPase oxidative inactivation. Co-administration of insulin (intranasally, 0.25 IU/rat) and α-T (orally, 50 mg/kg) led to a more pronounced normalization of the levels of Schiff bases, conjugated dienes and trienes and Na⁺,K⁺-ATPase activity than administration of each drug alone. Thus, α-T enhances the protective effects of insulin on cultured cortical neurons in oxidative stress and in the brain cortex of rats with cerebral ischemia/reperfusion injury.

AMPK activators for the prevention and treatment of neurodegenerative diseases

INTRODUCTION

As the global population ages at an unprecedented rate, the burden of neurodegenerative diseases is expected to grow. Given the profound impact illness like dementia exert on individuals and society writ large, researchers, physicians, and scientific organizations have called for increased investigation into their treatment and prevention. Both metformin and aspirin have been associated with improved cognitive outcomes. These agents are related in their ability to stimulate AMP kinase (AMPK). Momordica charantia, another AMPK activator, is a component of traditional medicines and a novel agent for the treatment of cancer. It is also being evaluated as a nootropic agent.

AREAS COVERED

This article is a comprehensive review which examines the role of AMPK activation in neuroprotection and the role that AMPK activators may have in the management of dementia and cognitive impairment. It evaluates the interaction of metformin, aspirin, and Momordica charantia, with AMPK, and reviews the literature characterizing these agents' impact on neurodegeneration.

EXPERT OPINION

We suggest that AMPK activators should be considered for the treatment and prevention of neurodegenerative diseases. We identify multiple areas of future investigation which may have a profound impact on patients worldwide.

Medicinal herbs and nutritional supplements for dementia therapy: potential therapeutic targets and clinical evidence

Spices and herbs have been used for medicinal purposes for centuries. Also, in the last decades, the use of different nutritional supplements has been implemented to treat all kinds of diseases, including those that present an alteration in cognitive functioning. Dementia is a clinical syndrome in which a person's mental and cognitive capacities gradually decline. As the disease progresses, the person's autonomy diminishes. As there is not an effective treatment to prevent progressive deterioration in many of these pathologies, nutritional interventions have been, and still are, one of the most widely explored therapeutic possibilities. In this review, we have discussed a great number of potentially interesting plants, nutritional derivatives and probiotics for the treatment of dementia around the world. Their action mechanisms generally involve neuroprotective effects via anti-inflammatory, antioxidant, anti-apoptotic, b-amyloid and tau anti-aggregate actions; brain blood flow improvement, and effects on synaptic cholinergic and dopaminergic neurotransmission, which may optimize cognitive performance in patients with cognitive impairment. As for their efficacy in patients with cognitive impairment and/or dementias, evidence is still scarce and/or their outcomes are controversial. We consider that many of these substances have promising therapeutic properties. Therefore, the scientific community has to continue with a more complete research focused on both identifying possible action mechanisms and carrying out clinical trials, preferably randomized double-blind ones, with a greater number of patients, a long-term follow-up, dose standardization and the use of current diagnosis criteria.

Associations of metabolomic profiles with circulating vitamin E and urinary vitamin E metabolites in middle-aged individuals

Vitamin E (α-tocopherol [α-TOH]) is transported in lipoprotein particles in blood, but little is known about the transportation of its oxidized metabolites. In the Netherlands Epidemiology of Obesity Study, we aimed to investigate the associations of 147 circulating metabolomic measures obtained through targeted nuclear magnetic resonance with serum α-TOH and its urinary enzymatic (α-CEHC) and oxidized (α-TLHQ) metabolites from 24-h urine quantified by liquid chromatography with tandem mass spectrometry. Multivariable linear regression analyses, in which multiple testing was taken into account, were performed to assess associations between metabolomic measures (determinants; standardized to mean = 0, SD = 1) and vitamin E metabolites (outcomes), adjusted for demographic factors. We analyzed 474 individuals (55% women, 45% men) with a mean (SD) age of 55.7 (6.0) y. Out of 147 metabolomic measures, 106 were associated (P < 1.34 × 10^-3) with serum α-TOH (median β [interquartile range] = 0.416 [0.383-0.466]), predominantly lipoproteins associated with higher α-TOH. The associations of metabolomic measures with urinary α-CEHC have directions similar to those with α-TOH, but effect sizes were smaller and non-significant (median β [interquartile range] = 0.065 [0.047-0.084]). However, associations of metabolomic measures with urinary α-TLHQ were markedly different from those with both serum α-TOH and urinary α-CEHC, with negative and small-to-null relations to most very-low-density lipoproteins and amino acids. Therefore, our results highlight the differences in the lipoproteins involved in the transportation of circulating α-TOH and oxidized vitamin E metabolites. This indicates that circulating α-TOH may be representative of the enzymatic but not the antioxidative function of vitamin E.

In Pursuit of Healthy Aging: Effects of Nutrition on Brain Function

Consuming a balanced, nutritious diet is important for maintaining health, especially as individuals age. Several studies suggest that consuming a diet rich in antioxidants and anti-inflammatory components such as those found in fruits, nuts, vegetables, and fish may reduce age-related cognitive decline and the risk of developing various neurodegenerative diseases. Numerous studies have been published over the last decade focusing on nutrition and how this impacts health. The main objective of the current article is to review the data linking the role of diet and nutrition with aging and age-related cognitive decline. Specifically, we discuss the roles of micronutrients and macronutrients and provide an overview of how the gut microbiota-gut-brain axis and nutrition impact brain function in general and cognitive processes in particular during aging. We propose that dietary interventions designed to optimize the levels of macro and micronutrients and maximize the functioning of the microbiota-gut-brain axis can be of therapeutic value for improving cognitive functioning, particularly during aging.

Quality of Life in Elders with Suspected Alzheimer Disease: An Urban Health Centers-Based Study from Iran

Background/Aims

Quality of life (QOL) and Alzheimer disease (AD) among older people have been recognized as public health challenges. Here, we investigated the association between QOL and AD in the elders.

Methods

In this cross-sectional study, elderly people were selected from urban health centers (Shiraz, Iran) by multistage cluster random sampling and were interviewed using LEIPAD (for QOL) and Montreal Cognitive Assessment (for AD) questionnaires. The data was analyzed using Mplus (version 6.12) and IBM SPSS (version 25) software.

Results

The participants consisted of 182 elderly with a mean age of 67 ± 5.05 years, and 95 (52.2%) of them were females. There were 161 (88.5%) and 130 (71.4%) cases educated up to 12 years and married, respectively. Furthermore, 46 (25.3%) had low-to-moderate QOL, and 132 (72.5%) were suspected to have AD. QOL was inversely associated with AD, and men (β = -0.310) were more affected than women (β = -0.290). AD (β = -0.298), age (β = -0.288), hypertension (β = -0.267), education (β = 0.260), and body mass index (β = -0.198) were determinants of QOL. Also, physical activity was indirectly associated with QOL (β = 0.076). AD was correlated with the cognitive functioning component of QOL (r = -0.72).

Conclusion

One elder out of 4, did not have desirable QOL and 3 elders out of 4 were suspected to have AD. AD can decrease QOL among the older people. Screening of the elders for AD is recommended to improve their QOL by health centers.

[Mild cognitive impairment: modern aspects of diagnostics and therapy]

The article provides a review of current literature on the diagnosis and treatment of mild cognitive impairment (MCI). MCI is not a common outcome of brain aging; it is an intermediate state between normal cognitive status and mild dementia. The MCI concept has been actively developing over the past few decades, a lot of knowledge and clinical experience has been accumulated, and numerous clinical trials are being conducted to develop effective methods of diagnosis and therapy. Treatment of pre-dementia cognitive disorders differs in many ways from therapy for dementia and has a better prognosis, therefore, it is recommended to diagnose and begin treating cognitive disorders as early as possible. The main possibilities of drug and non-drug therapy are described, with an emphasis on the use of the dopamine receptor agonist piribedil in the treatment of MCI and sensory deficit in elderly patients. The mechanisms of action of the drug are analyzed, data from the main clinical studies of the efficacy and safety of piribedil are presented: the positive effect of the drug on cognitive functions has been shown in more than 10 international clinical trials including about 7000 patients and in a number of post-marketing works performed on the Russian population of patients. Piribedil is successfully used for various types of cognitive disorders, both neurodegenerative and vascular, of mild to moderate severity.

Severity of subjective forgetfulness is associated with high dietary intake of copper in Japanese senior women: A cross-sectional study

This study investigated the relationship between subjective forgetfulness and the dietary intake of various nutrients in middle-aged and senior women. A cross-sectional study of the first-visit records of 245 Japanese women aged 40 or over was performed. The severity of subjective forgetfulness was classified according to the Menopausal Health-Related Quality of Life Questionnaire: none and mild ("unforgetful") or moderate and severe ("forgetful"). Dietary consumption of nutrients was estimated using the brief-type self-administered diet history questionnaire. The associations between the severity of subjective forgetfulness and intake of 43 major nutrients were evaluated using multivariate logistic regression analysis separately performed for two age groups: middle-aged (40-54 years, N = 166) and senior (55 years or over, N = 79). No nutrients were found to be significantly associated with subjective forgetfulness in the middle-aged group. In senior women, a significant positive relationship between the intake of copper and forgetfulness was found (adjusted odds ratio per 10 mg/kJ increase in copper intake: 1.25; 95% confidence interval: 1.08-1.50). Thus, high copper intake is positively associated with the severity of forgetfulness in Japanese senior women. Reducing copper consumption could help improve this symptom in this population.

Neuroprotection Against Oxidative Stress: Phytochemicals Targeting TrkB Signaling and the Nrf2-ARE Antioxidant System

Oxidative stress (OS) plays a critical role in the pathophysiology of several brain-related disorders, including neurodegenerative diseases and ischemic stroke, which are the major causes of dementia. The Nrf2-ARE (nuclear factor erythroid 2-related factor 2/antioxidant responsive element antioxidant) system, the primary cellular defense against OS, plays an essential role in neuroprotection by regulating the expressions of antioxidant molecules and enzymes. However, simultaneous events resulting in the overproduction of reactive oxygen species (ROS) and deregulation of the Nrf2-ARE system damage essential cell components and cause loss of neuron structural and functional integrity. On the other hand, TrkB (tropomyosin-related kinase B) signaling, a classical neurotrophin signaling pathway, regulates neuronal survival and synaptic plasticity, which play pivotal roles in memory and cognition. Also, TrkB signaling, specifically the TrkB/PI3K/Akt (TrkB/phosphatidylinositol 3 kinase/protein kinase B) pathway promotes the activation and nuclear translocation of Nrf2, and thus, confers neuroprotection against OS. However, the TrkB signaling pathway is also known to be downregulated in brain disorders due to lack of neurotrophin support. Therefore, activations of TrkB and the Nrf2-ARE signaling system offer a potential approach to the design of novel therapeutic agents for brain disorders. Here, we briefly overview the development of OS and the association between OS and the pathogenesis of neurodegenerative diseases and brain injury. We propose the cellular antioxidant defense and TrkB signaling-mediated cell survival systems be considered pharmacological targets for the treatment of neurodegenerative diseases, and review the literature on the neuroprotective effects of phytochemicals that can co-activate these neuronal defense systems.

Dietary interventions in mild cognitive impairment and dementia

Dietary intervention is an enticing approach in the fight against cognitive impairment. Nutritional supplements and dietetic counseling are relatively easy and benign interventions, but research has not yet yielded irrefutable evidence as to their clinical utility. Heterogeneity in the results of available clinical studies, as well as methodological and practical issues, does not allow replication and generalization of findings. The paper at hand reviews only randomized clinical trials of single nutrients, multi-nutrient formulations and dietary counseling in mild cognitive impairment and dementia of the Alzheimer's type focusing on both cognitive and functional outcomes. Thus far, folate, vitamin E, Ω-3 fatty acids, and certain multi-nutrient formulations have shown some preliminary promising results; larger, well-designed trials are needed to confirm these findings before nutritional elements can be incorporated in recommended clinical guidelines.

Ageing, age-related diseases and oxidative stress: What to do next?

Among other mechanisms, oxidative stress has been postulated to play an important role in the rate of ageing. Oxidative damage contributes to the hallmarks of ageing and essential components in pathological pathways which are thought to drive multiple age-related diseases. Nonetheless, results from studies testing the hypothesis of oxidative stress in ageing and diseases showed controversial results. While observational studies mainly found detrimental effects of high oxidative stress levels on disease status, randomized clinical trials examining the effect of antioxidant supplementation on disease status generally showed null effects. However, re-evaluations of these counterinitiative observations are required considering the lack of reliability and specificity of traditionally used biomarkers for measuring oxidative stress. To facilitate these re-evaluations, this review summarizes the basic knowledge of oxidative stress and the present findings regarding the role of oxidative damage in ageing and age-related diseases. Meanwhile, two approaches are highlighted, namely proper participants selection, together with the development of reliable biomarkers. We propose that oxidized vitamin E metabolites may be used to accurately monitor individual functional antioxidant level, which might serve as promising key solutions for future elucidating the impact of oxidative stress on ageing and age-related diseases.

Revisiting the intersection of amyloid, pathologically modified tau and iron in Alzheimer's disease from a ferroptosis perspective

The complexity of Alzheimer's disease (AD) complicates the search for effective treatments. While the key roles of pathologically modified proteins has occupied a central role in hypotheses of the pathophysiology, less attention has been paid to the potential role for transition metals overload, subsequent oxidative stress, and tissue injury. The association of transition metals, the major focus heretofore iron and amyloid, the same can now be said for the likely pathogenic microtubular associated tau (MAPT). This review discusses the interplay between iron, pathologically modified tau and oxidative stress, and connects many related discoveries. Basic principles of the transition to pathological MAPT are discussed. Iron, its homeostatic mechanisms, the recently described phenomenon of ferroptosis and purported, although still controversial roles in AD are reviewed as well as considerations to overcome existing hurdles of iron-targeted therapeutic avenues that have been attempted in AD. We summarize the involvement of multiple pathological pathways at different disease stages of disease progression that supports the potential for a combinatorial treatment strategy targeting multiple factors.

Vitamin E therapy prevents the accumulation of congophilic amyloid plaques and neurofibrillary tangles in the hippocampus in a rat model of Alzheimer's disease

OBJECTIVES

Vitamin E may have beneficial effects on oxidative stress and Aβ-associated reactive oxygen species production in Alzheimer's disease. But, the exact role of vitamin E as a treatment for Alzheimer's disease pathogenesis still needs to be studied. Hence, we examined the therapeutic effects of vitamin E on the density of congophilic amyloid plaques and neurofibrillary tangles in rats' hippocampi.

MATERIALS AND METHODS

Wistar rats were randomly assigned to control (no drug treatment), sham scopolamine (3 mg/kg)+saline and Sham scopolamine+sesame oil groups, and three experimental groups that received scopolamine+vitamin E (25, 50, and 100 mg/kg/day) daily for 14 days after scopolamine injection. The rats' brains were collected immediately following transcardial perfusion and fixed in 4% paraformaldehyde. Pathological brain alterations were monitored through Congo red and bielschowsky silver staining.

RESULTS

Scopolamine treatment led to a significant increase in the density of congophilic amyloid plaques and neurofibrillary tangles in the hippocampus. IP injection of vitamin E in three doses (25, 50, and 100 mg/kg/day) significantly reversed the scopolamine-induced increase of the congophilic amyloid plaque density and density of neurofibrillary tangles in the hippocampus. Although vitamin E (25 and 50 mg/kg/day) doses were also effective, but a 100 mg/kg/day dose of vitamin E was more effective in the reduction of congophilic amyloid plaque and neurofibrillary tangle density.

CONCLUSION

Vitamin E could exert a therapeutic effect in the reduction of congophilic amyloid plaque and neurofibrillary tangle density in the hippocampus of scopolamine-treated rats and it is useful for Alzheimer's disease.

Cognitive symptoms of Alzheimer's disease: clinical management and prevention

Alzheimer's disease (AD) is a progressive neurodegenerative disease characterized by the accumulation of amyloid β in the form of extracellular plaques and by intracellular neurofibrillary tangles, with eventual neurodegeneration and dementia. There is currently no disease-modifying treatment though several symptomatic medications exist with modest benefit on cognition. Acetylcholinesterase inhibitors have a consistent benefit across all stages of dementia; their benefit in mild cognitive impairment and prodromal AD is unproven. Memantine has a smaller benefit on cognition overall which is limited to the moderate to severe stages, and the combination of a cholinesterase inhibitor and memantine may have additional efficacy. Evidence for the efficacy of vitamin E supplementation and medical foods is weak but might be considered in the context of cost, availability, and safety in individual patients. Apparently promising disease-modifying interventions, mostly addressing the amyloid cascade hypothesis of AD, have recently failed to demonstrate efficacy so novel approaches must be considered.

Reformulating Pro-Oxidant Microglia in Neurodegeneration

In neurodegenerative diseases, microglia-mediated neuroinflammation and oxidative stress are central events. Recent genome-wide transcriptomic analyses of microglial cells under different disease conditions have uncovered a new subpopulation named disease-associated microglia (DAM). These studies have challenged the classical view of the microglia polarization state’s proinflammatory M1 (classical activation) and immunosuppressive M2 (alternative activation). Molecular signatures of DAM and proinflammatory microglia (highly pro-oxidant) have shown clear differences, yet a partial overlapping gene profile is evident between both phenotypes. The switch activation of homeostatic microglia into reactive microglia relies on the selective activation of key surface receptors involved in the maintenance of brain homeostasis (a.k.a. pattern recognition receptors, PRRs). Two relevant PRRs are toll-like receptors (TLRs) and triggering receptors expressed on myeloid cells-2 (TREM2), whose selective activation is believed to generate either a proinflammatory or a DAM phenotype, respectively. However, the recent identification of endogenous disease-related ligands, which bind to and activate both TLRs and TREM2, anticipates the existence of rather complex microglia responses. Examples of potential endogenous dual ligands include amyloid β, galectin-3, and apolipoprotein E. These pleiotropic ligands induce a microglia polarization that is more complicated than initially expected, suggesting the possibility that different microglia subtypes may coexist. This review highlights the main microglia polarization states under disease conditions and their leading role orchestrating oxidative stress.

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.

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.

Delineation of the Individual Effects of Vitamin E Isoforms on Early Life Incident Wheezing

OBJECTIVES

To test the hypothesis that maternal plasma alpha-tocopherol levels are associated with protection from childhood wheeze and that this protection is modified by gamma-tocopherol.

STUDY DESIGN

We conducted a prospective nested study in the Infant Susceptibility to Pulmonary Infections and Asthma Following Respiratory Syncytial Virus Exposure birth cohort of 652 children with postpartum maternal plasma vitamin E isoforms used as a surrogate for pregnancy concentrations. Our outcomes were wheezing and recurrent wheezing over a 2-year period, ascertained using validated questionnaires. We assessed the association of alpha- and gamma-tocopherol with wheezing outcomes using multivariable adjusted logistic regression, and tested for interaction between the isoforms with respect to the risk for wheezing outcomes.

RESULTS

Children with wheezing (n = 547, n = 167; 31%) and recurrent wheezing (n = 545, n = 55; 10.1%) over a 2-year period were born to mothers with significantly lower postpartum maternal plasma concentrations of alpha-tocopherol, P = .016 and P = .007, respectively. In analyses of IQR increases, alpha-tocopherol was associated with decreased risk of wheezing (aOR 0.70 [95% CI 0.53,0.92]) and recurrent wheezing (aOR 0.63 [95% CI 0.42,0.95]). For gamma-tocopherol, the aOR for wheezing was 0.79 (95% CI 0.56-1.10) and the aOR for recurrent wheezing was 0.56 (95% CI 0.33-0.94, with nonmonotonic association). The association of alpha-tocopherol with wheezing was modified by gamma-tocopherol (P interaction = .05).

CONCLUSIONS

Increases in postpartum maternal plasma alpha-tocopherol isoform concentrations were associated with decreased likelihood of wheezing over a 2-year period. Gamma-tocopherol modified this association.

Advances in developing novel therapeutic strategies for Alzheimer's disease

Alzheimer's Disease (AD), the most prevalent neurodegenerative disease of aging, affects one in eight older Americans. Nearly all drug treatments tested for AD today have failed to show any efficacy. There is a great need for therapies to prevent and/or slow the progression of AD. The major challenge in AD drug development is lack of clarity about the mechanisms underlying AD pathogenesis and pathophysiology. Several studies support the notion that AD is a multifactorial disease. While there is abundant evidence that amyloid plays a role in AD pathogenesis, other mechanisms have been implicated in AD such as tangle formation and spread, dysregulated protein degradation pathways, neuroinflammation, and loss of support by neurotrophic factors. Therefore, current paradigms of AD drug design have been shifted from single target approach (primarily amyloid-centric) to developing drugs targeted at multiple disease aspects, and from treating AD at later stages of disease progression to focusing on preventive strategies at early stages of disease development. Here, we summarize current strategies and new trends of AD drug development, including pre-clinical and clinical trials that target different aspects of disease (mechanism-based versus non-mechanism based, e.g. symptomatic treatments, lifestyle modifications and risk factor management).

Effect of dietary interventions in mild cognitive impairment: a systematic review

Diet has been investigated in relation to its ability to promote cognitive function. However, evidence is currently limited and has rarely been systematically reviewed, particularly in a mild cognitive impairment (MCI) population. This review examined the effect of diet on cognitive outcomes in MCI patients. A total of five databases were searched to find randomised controlled trial (RCT) studies, with diet as the main focus, in MCI participants. The primary outcome was incident dementia and/or Alzheimer's disease (AD) and secondary outcomes included cognitive function across different domains using validated neuropsychological tests. Sixteen studies met the inclusion criteria. There was a high degree of heterogeneity relating to the nature of the dietary intervention and cognitive outcomes measured, thus making study comparisons difficult. Supplementation with vitamin E (one study, n 516), ginkgo biloba (one study, n 482) or Fortasyn Connect (one study, n 311) had no significant effect on progression from MCI to dementia and/or AD. For cognitive function, the findings showed some improvements in performance, particularly in memory, with the most consistent results shown by B vitamins, including folic acid (one study, n 266), folic acid alone (one study, n 180), DHA and EPA (two studies, n 36 and n 86), DHA (one study, n 240) and flavonol supplementation (one study, n 90). The findings indicate that dietary factors may have a potential benefit for cognitive function in MCI patients. Further well-designed trials are needed, with standardised and robust measures of cognition to investigate the influence of diet on cognitive status.

Nutritional interventions and cognitive-related outcomes in patients with late-life cognitive disorders: A systematic review

There have been a large number of observational studies on the impact of nutrition on neuroprotection, however, there was a lack of evidence from randomized clinical trials (RCTs). In the present systematic review, from the 32 included RCTs published in the last four years (2014-2017) in patients aged 60 years and older with different late-life cognitive disorders, nutritional intervention through medical food/nutraceutical supplementation and multidomain approach improved magnetic resonance imaging findings and other cognitive-related biomarkers, but without clear effect on cognition in mild Alzheimer's disease (AD) and mild cognitive impairment (MCI). Antioxidant-rich foods (nuts, grapes, cherries) and fatty acid supplementation, mainly n-3 polyunsaturated fatty acids (PUFA), improved specific cognitive domains and cognitive-related outcomes in MCI, mild-to-moderate dementia, and AD. Antioxidant vitamin and trace element supplementations improved only cognitive-related outcomes and biomarkers, high-dose B vitamin supplementation in AD and MCI patients improved cognitive outcomes in the subjects with a high baseline plasma n-3 PUFA, while folic acid supplementation had positive impact on specific cognitive domains in those with high homocysteine.

Cerebral Hypoperfusion and Other Shared Brain Pathologies in Ischemic Stroke and Alzheimer's Disease

Newly emerged evidence reveals that ischemic stroke and Alzheimer's disease (AD) share pathophysiological changes in brain tissue including hypoperfusion, oxidative stress, immune exhaustion, and inflammation. A mechanistic link between hypoperfusion and amyloid β accumulation can lead to cell damage as well as to motor and cognitive deficits. This review will discuss decreased cerebral perfusion and other related pathophysiological changes common to both ischemic stroke and AD, such as vascular damages, cerebral blood flow alteration, abnormal expression of amyloid β and tau proteins, as well as behavioral and cognitive deficits. Furthermore, this review highlights current treatment options and potential therapeutic targets that warrant further investigation.

Chronic vitamin E deficiency impairs cognitive function in adult zebrafish via dysregulation of brain lipids and energy metabolism

Zebrafish (Danio rerio) are a recognized model for studying the pathogenesis of cognitive deficits and the mechanisms underlying behavioral impairments, including the consequences of increased oxidative stress within the brain. The lipophilic antioxidant vitamin E (α-tocopherol; VitE) has an established role in neurological health and cognitive function, but the biological rationale for this action remains unknown. In the present study, we investigated behavioral perturbations due to chronic VitE deficiency in adult zebrafish fed from 45 days to 18-months of age diets that were either VitE-deficient (E-) or VitE-sufficient (E+). We hypothesized that E- zebrafish would display cognitive impairments associated with elevated lipid peroxidation and metabolic disruptions in the brain. Quantified VitE levels at 18-months in E- brains (5.7 ± 0.1 nmol/g tissue) were ~20-times lower than in E+ (122.8 ± 1.1; n = 10/group). Using assays of both associative (avoidance conditioning) and non-associative (habituation) learning, we found E- vs E+ fish were learning impaired. These functional deficits occurred concomitantly with the following observations in adult E- brains: decreased concentrations of and increased peroxidation of polyunsaturated fatty acids (especially docosahexaenoic acid, DHA), altered brain phospholipid and lysophospholipid composition, as well as perturbed energy (glucose/ketone), phosphatidylcholine and choline/methyl-donor metabolism. Collectively, these data suggest that chronic VitE deficiency leads to neurological dysfunction through multiple mechanisms that become dysregulated secondary to VitE deficiency. Apparently, the E- animals alter their metabolism to compensate for the VitE deficiency, but these compensatory mechanisms are insufficient to maintain cognitive function.