High-dose B vitamin supplementation and cognitive decline in Alzheimer disease: a randomized controlled trial

Effects of folic acid supplementation on cognitive function and inflammation in elderly patients with mild cognitive impairment: A systematic review and meta-analysis of randomized controlled trials

OBJECT

The aim was to assess the effect of folic acid supplementation on cognitive function and inflammatory cytokines in elderly patients with mild cognitive impairment.

METHODS

From its inception until February 2024, four databases including Web of Science were searched. Two researchers independently screened the literature, assessed the quality, extracted data, and conducted a meta-analysis using RevMan.

RESULTS

The systematic review included seven studies (with a total of 1102 participants, mean age 65-80 years), seven of which were appropriate for meta-analysis. Although a small number of studies found relatively large heterogeneity, the majority of studies showed significant benefit from folic acid supplementation, including the FSIQ (823 individuals, standardized mean difference [SMD] = 8.36, 95 % confidence interval [CI] = 0.79 - 1.08), Arithmetic (823 individuals, SMD = 0.17, 95 % CI = -0.03-0.31), Information, SMD = 1.73, 95 % CI 0.41-3.05), Digit Span (823 individuals, SMD = 0.17, 95 % CI = -0.03 - 0.31), Block Design (823 individuals, SMD = 0.26, 95 % CI 0.03-0.49), Picture Completion (823 individuals, SMD = 0.27, 95 % CI = -0.15 - 0.69) and Picture Arrangement (823 individuals, SMD = -0.12, 95 % CI = -0.26 - 0.01). Finally, folic acid supplementation had a significant effect on the reduction of most inflammatory cytokines, blood biomarkers of Alzheimer's disease, and Hcy.

CONCLUSIONS

Folic acid supplementation seems to have a positive impact on cognitive function in older adults with mild cognitive impairment, but further evidence of its effectiveness in improving inflammatory cytokines is needed from high-quality studies.

Effect of long-term pharmacological treatments on Alzheimer disease: A systematic review and network meta-analysis

BACKGROUND

To analyze and compare the pharmacological treatments for Alzheimer disease (AD), we will conduct a systematic review and network meta-analysis focusing on their efficacy and safety over a duration exceeding 1 year.

METHODS

We searched the databases of PubMed, Scopus, EMBASE, Web of Science, the Cochrane Central Register of Controlled Trials, and CNKI until July 30, 2023, for randomized controlled trials (RCTs) evaluating pharmacological treatments for AD.

RESULTS

Seventeen RCTs, comprising 7214 participants, investigated the efficacy of the following drugs: Donepezil, Rivastigmine, Galantamine, Memantine, Ginkgo biloba extract (EGb), Atorvastatin-calcium and Vitamin B in the treatment of AD. The network meta-analysis resulted indicated that placebo demonstrated greater effectiveness compared to Atorvastatin-calcium 80 mg (mean different [MD] = -6.93, confidence interval [CI] -11.57, -2.29) and Rivastigmine 12 mg (MD = -3.33, CI -6.56, -0.09). EGb120 mg exhibited a greater improvement in cognition compared to Atorvastatin-calcium 80 mg (MD = 7.77, CI 2.07, 13.46) and Rivastigmine 12 mg + EGb120 mg (MD = 9.92, CI 1.32, 17.22). EGb 120 mg emerged as the most efficient intervention for cognition, while placebo demonstrated the least harm over a period exceeding 1 year.

CONCLUSIONS

In this network meta-analysis of studies of patients with AD and a follow-up period of at least 1 year, EGb 120 mg demonstrated cognitive benefits, while placebo posed the least harm for AD. More RCTs are required to address the uncertainty surrounding the efficacy of medication.

Associations among dietary 1-carbon metabolism nutrients, genetic risk, and Alzheimer disease: a prospective cohort study

BACKGROUND

The associations between 1-carbon metabolism (OCM) nutrients (methionine, folate, vitamin B-6, and vitamin B-12) and Alzheimer disease (AD) remains inconclusive.

OBJECTIVES

This study aimed to investigate the association of dietary OCM nutrients with subsequent risk of AD and further assess whether participants with high genetic risk for AD might benefit from dietary OCM nutrients.

METHODS

We analyzed data from 192,214 participants who completed at least one 24-h dietary questionnaire and had no previous history of AD based on the UK Biobank. Nutrients intake was calculated using McCance and Widdowson's The Composition of Food and USDA's Food and Nutrient Database for Dietary Studies. Cox proportional models with restricted cubic splines were applied to explore the associations.

RESULTS

Over a median follow-up of 13.35 y, 959 cases of AD (41 early-onset cases and 918 late-onset cases) were identified. Compared with those in the low-intake OCM group (quartile 1), participants in the high-intake OCM group (quartile 4) had reduced risk of developing AD. The corresponding hazard ratios (HRs) and 95% confidence intervals (CIs) for methionine, folate, vitamin B-6, and vitamin B-12 intake were 0.66 (0.54, 0.80), 0.71 (0.58, 0.87), 0.71 (0.59, 0.87), and 0.77 (0.64, 0.93), respectively. Similar associations were observed in late-onset AD. In early-onset AD, high methionine and vitamin B-12 intake were associated with 70% (HR: 0.30; 95% CI: 0.10, 0.86) and 71% (HR: 0.29; 95% CI: 0.09, 0.96) reduction in risk, respectively. Participants with low genetic risk and high OCM nutrients intake had >75% reduced AD risk compared with high-risk, low-intake participants.

CONCLUSIONS

In this prospective cohort study, we found that higher intake of OCM nutrients is associated with reduced risk of AD. Participants with high genetic risk of AD are more likely to benefit from dietary OCM nutrients intake.

Unveiling the Therapeutic Potential of Folate-Dependent One-Carbon Metabolism in Cancer and Neurodegeneration

Cellular metabolism is crucial for various physiological processes, with folate-dependent one-carbon (1C) metabolism playing a pivotal role. Folate, a B vitamin, is a key cofactor in this pathway, supporting DNA synthesis, methylation processes, and antioxidant defenses. In dividing cells, folate facilitates nucleotide biosynthesis, ensuring genomic stability and preventing carcinogenesis. Additionally, in neurodevelopment, folate is essential for neural tube closure and central nervous system formation. Thus, dysregulation of folate metabolism can contribute to pathologies such as cancer, severe birth defects, and neurodegenerative diseases. Epidemiological evidence highlights folate's impact on disease risk and its potential as a therapeutic target. In cancer, antifolate drugs that inhibit key enzymes of folate-dependent 1C metabolism and strategies targeting folate receptors are current therapeutic options. However, folate's impact on cancer risk is complex, varying among cancer types and dietary contexts. In neurodegenerative conditions, including Alzheimer's and Parkinson's diseases, folate deficiency exacerbates cognitive decline through elevated homocysteine levels, contributing to neuronal damage. Clinical trials of folic acid supplementation show mixed outcomes, underscoring the complexities of its neuroprotective effects. This review integrates current knowledge on folate metabolism in cancer and neurodegeneration, exploring molecular mechanisms, clinical implications, and therapeutic strategies, which can provide crucial information for advancing treatments.

A Comparative Study Evaluating the Effectiveness of Folate-Based B Vitamin Intervention on Cognitive Function of Older Adults under Mandatory Folic Acid Fortification Policy: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

The policies regarding the mandatory fortification of food with folic acid (FA) may impact the effectiveness of folate-based B vitamin treatment on cognitive function in older adults. We critically and systematically review the literature to assess whether food fortification policies affect folate-based B vitamin treatment efficacy on cognition function in older adults. Electronic databases, including PubMed, Web of Science, and CNKI, were searched for "Cognitive Function", "Folate", and "Older Adults". The study had specific criteria for inclusion, which were as follows: (1) the studies should initially have randomized controlled trials that were conducted on older adults aged 60 or above; (2) the studies must assess the relationship between folate status and cognitive performance; and (3) the studies should clarify the policies regarding food fortification with FA. This review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) reporting guidelines. Two reviewers independently extracted all the data, and any discrepancies were resolved by consensus. All the data collected were compiled, compared, and analyzed critically. Random effects models were used to assess the effects of interventions. The systematic review included fifty-one articles involving 42,768 participants. Of these, the 23 articles were included in the meta-analysis. The meta-analysis on the effects of folate-based B vitamin supplementation on cognitive function showed a significant overall impact (Z = 3.84; p = 0.0001; SMD, 0.18; 95% CI, 0.09, 0.28). Further analysis revealed that FA food fortification policies were not implemented in countries where folate-based B vitamin supplementation improved cognitive impairment in older adults (Z = 3.75; p = 0.0002; SMD, 0.27; 95% CI, 0.13, 0.40). However, the FA intervention did not have significant outcomes in areas where FA food fortification policies were mandatory (Z = 0.75; p = 0.45; SMD, 0.03; 95% CI, -0.06, 0.13). Supplementing with oral folic acid, alone or in combination, has been linked to improved cognitive performance in older adults. While mandatory FA fortification has the improved folic acid status, additional folate-based B vitamin supplements do not appear to influence cognitive function.

7,8-Dihydroxyflavone is a direct inhibitor of human and murine pyridoxal phosphatase

Vitamin B6 deficiency has been linked to cognitive impairment in human brain disorders for decades. Still, the molecular mechanisms linking vitamin B6 to these pathologies remain poorly understood, and whether vitamin B6 supplementation improves cognition is unclear as well. Pyridoxal 5'-phosphate phosphatase (PDXP), an enzyme that controls levels of pyridoxal 5'-phosphate (PLP), the co-enzymatically active form of vitamin B6, may represent an alternative therapeutic entry point into vitamin B6-associated pathologies. However, pharmacological PDXP inhibitors to test this concept are lacking. We now identify a PDXP and age-dependent decline of PLP levels in the murine hippocampus that provides a rationale for the development of PDXP inhibitors. Using a combination of small-molecule screening, protein crystallography, and biolayer interferometry, we discover, visualize, and analyze 7,8-dihydroxyflavone (7,8-DHF) as a direct and potent PDXP inhibitor. 7,8-DHF binds and reversibly inhibits PDXP with low micromolar affinity and sub-micromolar potency. In mouse hippocampal neurons, 7,8-DHF increases PLP in a PDXP-dependent manner. These findings validate PDXP as a druggable target. Of note, 7,8-DHF is a well-studied molecule in brain disorder models, although its mechanism of action is actively debated. Our discovery of 7,8-DHF as a PDXP inhibitor offers novel mechanistic insights into the controversy surrounding 7,8-DHF-mediated effects in the brain.

Role of vitamin B12 and folic acid in treatment of Alzheimer's disease: a meta-analysis of randomized control trials

Vitamin B12 and folic acid could reduce blood homocysteine levels, which was thought to slow down the progression of Alzheimer's disease (AD), but previous studies regarding the effect of vitamin B12 and folic acid in treatment of AD have not reached conclusive results. We searched PubMed and Embase until January 12, 2023. Only randomized control trials involving participants clearly diagnosed with AD and who received vitamin B12 and folic acid were enrolled. Five studies that met the criteria were selected for inclusion in the meta-analysis. Changes in cognitive function were measured based on either the Mini-Mental State Examination (MMSE) or the Alzheimer's Disease Assessment Scale-Cognitive Subscale (ADAS-Cog). Changes in daily life function and the level of blood homocysteine were also investigated. After a 6-month treatment, administration of vitamin B12 and folic acid improved the MMSE scores more than placebo did (SMD = 0.21, 95% CI = 0.01 to 0.32, p = 0.04) but did not significantly affect ADAS-Cog scores (SMD = 0.06, 95% CI = -0.22 to 0.33, p = 0.68) or measures of daily life function. Blood homocysteine levels were significantly decreased after vitamin B12 and folic acid treatment. Participants with AD who received 6 months of vitamin B12 and folic acid supplementation had better MMSE scores but had no difference in ADAS-Cog scores. Daily life function did not improve after treatment.

Supplements for cognitive ability in patients with mild cognitive impairment or Alzheimer's disease: a protocol for systematic review and network meta-analysis of randomised controlled trials

INTRODUCTION

Considering the increasing incidence of Alzheimer's disease (AD) and mild cognitive impairment (MCI) worldwide, there is an urgent need to identify efficacious, safe and convenient treatments. Numerous investigations have been conducted on the use of supplements in this domain, with oral supplementation emerging as a viable therapeutic approach for AD or MCI. Nevertheless, given the multitude of available supplements, it becomes imperative to identify the optimal treatment regimen.

METHODS AND ANALYSIS

Eight academic databases and three clinical trial registries will be searched from their inception to 1 June 2023. To identify randomised controlled trials investigating the effects of supplements on patients with AD or MCI, two independent reviewers (X-YZ and Y-QL) will extract relevant information from eligible articles, while the risk of bias in the included studies will be assessed using the Rob 2.0 tool developed by the Cochrane Collaboration. The primary outcome of interest is the overall cognitive function. Pair-wise meta-analysis will be conducted using RevMan V.5.3, while network meta-analysis will be carried out using Stata 17.0 and ADDIS 1.16.8. Heterogeneity test, data synthesis and subgroup analysis will be performed if necessary. The GRADE system will be employed to assess the quality of evidence. This study is scheduled to commence on 1 June 2023 and conclude on 1 October 2023.

ETHICS AND DISSEMINATION

Ethics approval is not required for systematic review and network meta-analysis. The results will be submitted to a peer-reviewed journal or at a conference.

TRIAL REGISTRATION NUMBER

PROSPERO (CRD42023414700).

Effects of folic acid supplementation on cognitive impairment: A meta-analysis of randomized controlled trials

OBJECTIVE

With the increasing number of patients with cognitive impairment, nonpharmacological ways to delay cognitive impairment have attracted people's attention, such as lifestyle changes and nutritional supplementation. Folic acid supplementation appears to be a promising treatment option. However, it remains controversial whether folic acid supplementation is effective in delaying adult's cognitive impairment. Therefore, we conducted a meta-analysis to analyze the effects of folic acid supplementation on different cognitive impairments.

METHODS

We systematically searched PubMed, Web of Science, EMbase, Cochrane Central Register of Controlled Trials, China National Knowledge Infrastructure (CNKI), WanFang and VIP databases for randomized controlled trials on January 22, 2024. The included population comprised those diagnosed with cognitive impairment. We included trials that compared folic acid treatment with placebo, other dosing regimens, or other intervention controls. Conducting quality evaluation of included studies according to the Cochrane Risk of Bias tool. Statistical analyses were performed using Review Manager software.

RESULTS

Twenty-two trials, including 3604 participants, met inclusion criteria. Compared with controls, the cognitive function of Alzheimer's disease (AD) patients showed improvement with folic acid supplementation: supplementation with < 3 mg (standardized mean differences (SMD) = 0.15, 95% confidence interval (CI) -0.10 to 0.41), and supplementing with ≥ 3 mg folic acid could improve cognitive function in AD patients (SMD = 1.03, 95% CI 0.18 to 1.88). Additionally, it reduced homocysteine (HCY) levels (mean differences (MD) = -4.74, 95% CI -8.08 to -1.39). In mild cognitive impairment (MCI) patients, cognitive function improved with folic acid supplementation: supplementation with > 400 μg (SMD = 0.38, 95% CI 0.13 to 0.63), and supplementation with ≤ 400 μg (SMD = 1.10, 95% CI 0.88 to 1.31). It also reduced HCY levels at intervention ≤ 6 months (MD = -3.93, 95% CI -5.05 to -2.82) and intervention > 6 months (MD = -4.38, 95% CI -5.15 to -3.61). However, supplementing with folic acid did not improve cognitive function in vascular cognitive impairment (VCI) patients, with folic acid supplements < 3 mg (SMD = -0.07, 95% CI -0.23 to -0.08), folic acid supplements ≥ 3 mg (SMD = 0.46, 95% CI -0.57 to 1.49), however, it reduced HCY levels at intervention > 6 months (MD = -5.91, 95% CI -7.13 to -4.69) and intervention ≤ 6 months (MD = -11.15, 95% CI -12.35 to -9.95).

CONCLUSIONS

Supplement folic acid is beneficial to the cognitive profile of patients with MCI, supplementation with ≥ 3 mg folic acid can improve cognitive function in AD patients.

A Combinational Therapy for Preventing and Delaying the Onset of Alzheimer's Disease: A Focus on Probiotic and Vitamin Co-Supplementation

Alzheimer's disease is a progressive neurodegenerative disorder with a complex etiology, and effective interventions to prevent or delay its onset remain a global health challenge. In recent years, there has been growing interest in the potential role of probiotic and vitamin supplementation as complementary strategies for Alzheimer's disease prevention. This review paper explores the current scientific literature on the use of probiotics and vitamins, particularly vitamin A, D, E, K, and B-complex vitamins, in the context of Alzheimer's disease prevention and management. We delve into the mechanisms through which probiotics may modulate gut-brain interactions and neuroinflammation while vitamins play crucial roles in neuronal health and cognitive function. The paper also examines the collective impact of this combinational therapy on reducing the risk factors associated with Alzheimer's disease, such as oxidative stress, inflammation, and gut dysbiosis. By providing a comprehensive overview of the existing evidence and potential mechanisms, this review aims to shed light on the promise of probiotic and vitamin co-supplementation as a multifaceted approach to combat Alzheimer's disease, offering insights into possible avenues for future research and clinical application.

Impacts of high-dose riboflavin on cytotoxicity, antioxidant, growth, reproductive gene expressions, and genotoxicity in the rainbow trout gonadal cells

Riboflavin (vitamin B2 found in food) is a precursor of flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD), which study as coenzymes for a variety of cellular processes including biosynthesis, homocysteine metabolism, detoxification, and various oxidation and reduction reactions. Although studies on the symptoms resulting from riboflavin deficiency are intense, studies on the effects of high doses of riboflavin are almost absent. This report aimed to examine the actions of riboflavin on cell viability, the transcriptional expressions of antioxidant enzyme (gsr and gpx1a), growth (gh1, igf1, and igf2), the reproductive (bol) genes and DNA damage in the rainbow trout gonad cells (RTG-2) for 48 h. All concentrations of riboflavin (3.125, 6.25, 12.5, 25, 50, and 100 μM) significantly reduced the RTG-2 cell viability. Riboflavin (LD50: 12.5 μM) significantly downregulated the transcriptional expressions of gpx1a, igf1, and bol genes, while it non-significantly upregulated or downregulated the transcriptional expression of gsr, igf2, and gh1 genes in the RTG-2 cells in comparison to the control group for 48 h. The comet assay demonstrated that riboflavin significantly raised tail DNA% >10% DMSO (positive control). Based on the outcomes, high doses of riboflavin exhibit the potential to have a role in cellular mechanisms, including especially reproduction, DNA damage, and cell death.

Use of Complementary and Integrative Medicine for Alzheimer's Disease and Cognitive Decline

Integrative medicine takes a holistic approach because it considers multiple aspects of the individual. This includes a person's physical, emotional, interpersonal, behavioral, nutritional, environmental, and spiritual dimensions of wellbeing that contribute to the Whole Person Health. There is increasing interest and popularity of integrative approaches to treating cognitive decline and dementia because of the multifactorial nature of aging and the limited pharmacological interventions available in treating cognitive decline and dementia, particularly Alzheimer's disease, the most common type of dementia. This review summarizes the existing evidence using complementary and integrative medicine therapies in cognitive decline and Alzheimer's disease. This includes the use of mind-body therapies, lifestyle interventions (nutritional, physical exercise, stress reduction), and other integrative modalities. Unfortunately, there are still limited studies available to guide clinicians despite the increasing popularity of integrative treatments.

The effects of the interplay between vitamins, antibiotics, and gut microbiota on the pathogenesis and progression of dementia: A systematic review and meta-analysis

Background

Given that there is already evidence of a neural network that connects the brain and gut and that the gut microbiota actively modulates gut health, it is crucial to know which foods, supplements, and medications to use or avoid when treating any disease that causes dementia or cognitive impairment. Previous research has examined the relationships between vitamins, antibiotics, and gut microbiota and the correlations between these factors and dementia. The question arises of how these three factors interact together and if evidence suggests one element is more important than the others in the pathogenesis and development of dementia.

Methods

The Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) standards were followed when conducting this review. The papers' publication dates varied from (2012-2022). Cochrane/EMBASE, PEDro, and PubMed/Medline databases were searched. The precise terms "gut microbiota," vitamins," antibiotics," and "dementia" were included in the search method, along with the conjunctions "OR" and "AND."

Results

Gut dysbiosis has a significant impact on cognition, brain function, and the development and progression of dementia. The two most popular probiotics used in studies linked to cognition benefits were Lactobacillus and Bifidobacterium. Numerous scales were used to evaluate cognition, but the mini-mental state examination was the most popular, and the most prevalent impairment was Alzheimer's disease. The supplements with the most significant impact on gut microbiota were vitamin B-12 and folic acid.

Conclusion

This systematic review concluded that vitamins, gut microbiota and antibiotics have a close association with the development of dementia. More research is required to establish causality and elucidate the underlying mechanisms because there is still little evidence connecting the interactions of vitamins, medications, and microbiota with dementia. The complexity of interactions between genetics, lifestyle factors, and comorbidities, as well as the heterogeneity of dementia, may make it more challenging to interpret the findings.

Spinacia Oleracea: Exploring the Therapeutic Potential in Persian Medicine and Modern Pharmacology

BACKGROUND

Spinach is a widely cultivated dark leafy vegetable highly regarded for its medicinal properties in traditional Persian medicine. It is rich in vitamins, minerals, flavonoids, carotenoids, and other bioactive compounds, and this review aims to explore the historical applications of spinach in Persian medicine and juxtapose them with current scientific evidence. Despite its historical significance, there remains a need to comprehensively evaluate and integrate traditional knowledge with modern research on the therapeutic benefits of spinach.

METHODS

To achieve this, a comprehensive search was conducted in Persian medicine references and scientific databases to gather information on the traditional uses, chemical composition, and pharmacological effects of spinach. Studies that met the inclusion criteria were meticulously categorized, and relevant data were analyzed to draw insightful comparisons.

RESULTS

Persian medicine describes spinach as a nutrient-rich, laxative, and fast-digesting agent with therapeutic effects on inflammation, lung diseases, back pain, sore throats, jaundice, urinary disorders, joint pain, eye inflammation, insomnia, dementia, and more. Modern studies have substantially corroborated these traditional uses, revealing that spinach possesses antioxidant, anti-inflammatory, anti-cancer, blood sugar-lowering, lipid-lowering, anti-obesity, neurological, ocular, and musculoskeletal effects.

CONCLUSION

Spinach exhibits a wide range of beneficial effects on various health conditions. Its widespread availability, low cost, and exceptional nutritional richness position it as a promising candidate for further investigation. Future studies should explore the clinical effectiveness of spinach in various diseases, while taking into consideration the principles emphasized in Persian medicine to guide research and inform therapeutic strategies.

Study Partner Type and Adverse Event Reporting in Mild-to-Moderate Alzheimer's Disease Clinical Trials

Background

In randomized clinical trials (RCTs), monitoring adverse events (AEs) and serious AEs (SAEs) is critical. All Alzheimer's disease (AD) RCTs require participants to enroll with a study partner.

Objective

We examined AE reporting rates in mild-to-moderate AD trials and their associations with study partner type.

Methods

We estimated AE reporting rates using placebo data from seven independent RCTs conducted by the Alzheimer's Disease Cooperative Study. We assessed the heterogeneity of reporting rates as a function of visits using generalized estimating equations. In the primary analysis, we tested the hypotheses that the rates of reporting differed by study partner type and time they spent with the participant weekly using Poisson regression with robust variance estimation. In all regression models, log-transformed total patient years was included.

Results

The estimated reporting rates were 2.83 (95% CI: 2.66, 3.02), 1.18 (95% CI: 1.09, 1.28), 0.23 (95% CI: 0.19, 0.27), and 0.28 (95% CI: 0.24, 0.33) events per participant year for grade 1-3 AEs and SAEs, respectively. We estimated that greater number of visits per year was associated with increased reporting for grade 1-2 AEs and SAEs. We did not find evidence to suggest that AE reporting differed by study partner type or by time the study partner spent with the participant.

Conclusions

Study partner type and time the study partner spent with the participant did not appear to impact AE reporting. Estimated reporting rates may be useful to evaluate safety in future studies, particularly those with no control arm and similar visit frequencies.

Serum vitamin B12 concentration is associated with improved memory in older individuals with higher adherence to the Mediterranean diet

BACKGROUND & AIMS

Vitamin B12 plays a crucial role in cognition, but its effect might be regulated by the presence of other micronutrients, such as folate. The aim was to evaluate the effects of vitamin B12 on cognitive performance according to adherence to the Mediterranean diet, and whether the Mediterranean diet also results in increased folate or vitamin B12 levels.

METHODS

This is a cohort study nested in a randomized controlled clinical trial performed in Hospital Clinic in Barcelona, Spain. A total of 170 participants of the PREDIMED trial (Barcelona - Hospital Clinic site) aged 55-80 years at high cardiovascular risk were included. Adherence to the Mediterranean diet was assessed using a validated 14-item questionnaire, memory function was evaluated with a battery of neuropsychological tests and serum vitamin B12 and folate were determined using an automated electrochemiluminiscence immunoassay system.

RESULTS

In the multivariable adjusted linear regression model, serum vitamin B12 concentration presented a significant correlation with memory function (r2 = 0.57; P = 0.028) in participants with high adherence to the Mediterranean diet whereas the correlation was weak and inverse for those who presented a low adherence to the Mediterranean diet (r2 = 0.37, P = 0.731). Mediterranean diet adherence showed a positive association with serum folate, but not with serum vitamin B12.

CONCLUSIONS

In an older Mediterranean population at high cardiovascular risk, changes in serum vitamin B12 correlate with better memory function only in the context of a high adherence to the Mediterranean pattern, suggesting that the effects of vitamin B12 goes further than a mere nutritional requirement.

INSTITUTIONAL REVIEW BOARD STATEMENT

The study was conducted according to the guidelines of the Declaration of Helsinki and was approved by the Institutional Review Board of the 11 participating centres. The study was registered with the International Standard Randomized Controlled Trial Number (ISRCTN) 35739639 (https://www.isrctn.com/ISRCTN35739639).

Effect of nutritional supports on malnutrition, cognition, function and biomarkers of Alzheimer's disease: a systematic review

AIM

To summarize the nutritional supplementation on biochemical parameters, cognition, function, Alzheimer's Disease (AD) biomarkers and nutritional status.

MATERIALS AND METHODS

PubMed, Web of Science, Korean Journal Database, Russian Science Citation Index, SciELO Citation Index, Cochrane Library and Scopus databases were searched until 16 April 2021. 22.193 records in total were reached according to inclusion and exclusion criteria. Included Studies were evaluated through the Modified Jadad Scale and gathered under four subheadings.

RESULTS

Forty-eight studies with a total of 7009 AD patients were included. Souvenaid, ONS (368 ± 69 kcal), Vegenat-med, 500 mg Resveratrol, ONS (200 mL) were effective nutritional supplements on promoting weight gain and protecting malnutrition status but showed conflicting results in Body mass index, Mid-Upper-Arm Circumference and Triceps Skin Fold Thickness. ONS and a lyophilized whole supplementation Vegenat-med intake made an increase in MNA scores. While all nutritional supplements showed controversial results in biochemical parameters but caused a decrease in Hcy levels which caused reductions in brain Aβ plaque (increase serum Aβ), p-Tau and cognitive improvement. Folic acid and vitamin D decreased serum APP, BACE1, BACE1mRNA. Resveratrol, Hericium erinaceus mycelia, vitamin D and Betaine supplements improved cognitive, functional prognosis and quality of life unlike other nutritional supplements had no effect on cognitive scales.

CONCLUSIONS

Better designed trials with holistic measures are needed to investigate the effect of nutritional support on the AD biomarkers, cognitive status, biochemical parameters and functional states. Also, more beneficial results can be obtained by examining the simultaneous effects of nutritional supplements with larger sample groups.

Comprehensive Review of Nutraceuticals against Cognitive Decline Associated with Alzheimer's Disease

Nowadays, nutraceuticals are being incorporated into functional foods or used as supplements with nonpharmacological approaches in the prevention and management of several illnesses, including age-related conditions and chronic neurodegenerative diseases. Nutraceuticals are apt for preventing and treating such disorders because of their nontoxic, non-habit-forming, and efficient bioactivities for promoting neurological well-being due to their ability to influence cellular processes such as neurogenesis, synaptogenesis, synaptic transmission, neuro-inflammation, oxidative stress, cell death modulation, and neuronal survival. The capacity of nutraceuticals to modify all of these processes reveals the potential to develop food-based strategies to aid brain development and enhance brain function, prevent and ameliorate neurodegeneration, and possibly reverse the cognitive impairment observed in Alzheimer's disease, the most predominant form of dementia in the elderly. The current review summarizes the experimental evidence of the neuroprotective capacity of nutraceuticals against Alzheimer's disease, describing their mechanisms of action and the in vitro and in vivo models applied to evaluate their neuroprotective potential.

Effects of informant replacement in Alzheimer's disease clinical trials

INTRODUCTION

Alzheimer's disease (AD) trials require enrollment with an informant.

METHODS

We assessed relationships between informant replacement and Alzheimer's Disease Cooperative Study Activities of Daily Living (ADCS-ADL) scores across four AD trials. Using generalized estimating equations, we examined associations between replacement and change in ADCS-ADL between successive visits. We used analysis of covariance to estimate the association between replacement and 18-month change from baseline, and an F-test to compare the variance of this change.

RESULTS

Among 1336 participants, 63 (≈5%) experienced replacement. Between-visit mean change in ADCS-ADL was 2.44 points lower comparing replacement to stable informants (95% confidence interval [CI]: -3.91, -0.98). The difference in between-visit mean absolute change was 2.38 points (95% CI: 1.24, 3.52). Replacement was not significantly associated with an 18-month change from baseline. The ratio of variances (replacement/stable) was 1.80 (95% CI: 1.19, 2.99).

DISCUSSION

Informant replacement is associated with bias and increased variability between visits and increased variance for overall ADCS-ADL.

The Role of Micronutrients in Neurological Disorders

Trace elements and vitamins, collectively known as micronutrients, are essential for basic metabolic reactions in the human body. Their deficiency or, on the contrary, an increased amount can lead to serious disorders. Research in recent years has shown that long-term abnormal levels of micronutrients may be involved in the etiopathogenesis of some neurological diseases. Acute and chronic alterations in micronutrient levels may cause other serious complications in neurological diseases. Our aim was to summarize the knowledge about micronutrients in relation to selected neurological diseases and comment on their importance and the possibilities of therapeutic intervention in clinical practice.

The Role of One-Carbon Metabolism in Healthy Brain Aging

Aging results in more health challenges, including neurodegeneration. Healthy aging is possible through nutrition as well as other lifestyle changes. One-carbon (1C) metabolism is a key metabolic network that integrates nutritional signals with several processes in the human body. Dietary supplementation of 1C components, such as folic acid, vitamin B12, and choline are reported to have beneficial effects on normal and diseased brain function. The aim of this review is to summarize the current clinical studies investigating dietary supplementation of 1C, specifically folic acid, choline, and vitamin B12, and its effects on healthy aging. Preclinical studies using model systems have been included to discuss supplementation mechanisms of action. This article will also discuss future steps to consider for supplementation. Dietary supplementation of folic acid, vitamin B12, or choline has positive effects on normal and diseased brain function. Considerations for dietary supplementation to promote healthy aging include using precision medicine for individualized plans, avoiding over-supplementation, and combining therapies.

Association between dietary niacin intake and cognitive function in the elderly: Evidence from NHANES 2011-2014

Recent studies have shown an inconsistent association between dietary niacin and cognitive function. And this remains unclear in the American outpatient population. The aim of this study was to assess whether there is an association between dietary niacin and cognitive performance in an older American population aged ≥60 years. A total of 2523 participants from the National Health and Nutrition Examination Survey (NHANES) 2011-2014 were enrolled. Cognitive function was assessed by the CERAD Word Learning (CERAD-WL) test, the CERAD Delayed Recall (CERAD-DR) test, the Animal Fluency test (AFT), and the Digit Symbol Substitution test (DSST). Cognitive impairment that meets one of the four scoring conditions listed above is defined as low cognitive function. Dietary niacin intake was obtained from 2 days of a 24-h recall questionnaire. Based on the quartiles of dietary niacin intake, they were divided into four groups: Q1 (<15.51 mg), Q2 (15.51-20.68 mg), Q3 (20.69-26.90 mg), and Q4 (>26.91 mg). The stability of the results was assessed using multifactorial logistic regression, restricted cubic spline (RCS) models, and sensitivity stratified analysis. More than half of the participants had cognitive impairment (52.52%). In the fully adjusted model, niacin was associated with a significantly reduced risk of cognitive impairment in Q3 and Q4 compared with the Q1 group (OR: 0.610, 95% CI: 0.403, 0.921, p = .022; OR: 0.592, 95% CI: 0.367, 0.954, p = .034). Meanwhile, niacin was negatively associated with poor cognition as assessed by the CERAD-WL test, CERAD test, AFT, and DSST. An L-shaped dose-response relationship between dietary niacin and cognitive function was observed in all participants (nonlinear p < .001). There were also interactions that existed in populations with different carbohydrate intakes and cholesterol intakes (p for interaction = .031, p for interaction = .005). These findings provide new evidence for the potential role of dietary niacin intake on cognitive function in the elderly.

Bioinorganic Chemistry of Micronutrients Related to Alzheimer's and Parkinson's Diseases

Metal ions are fundamental to guarantee the regular physiological activity of the human organism. Similarly, vitamins play a key role in many biological functions of the metabolism, among which are coenzymes, redox mediators, and antioxidants. Due to their importance in the human organism, both metals and vitamins have been extensively studied for their involvement in neurodegenerative diseases (NDs). However, the full potential of the interaction between vitamins and metal ions has not been fully explored by researchers yet, and further investigation on this topic is needed. The aim of this review is to provide an overview of the scientific literature on the implications of vitamins and selected metal ions in two of the most common neurodegenerative diseases, Alzheimer's and Parkinson's disease. Furthermore, vitamin-metal ion interactions are discussed in detail focusing on their bioinorganic chemistry, with the perspective of arousing more interest in this fascinating bioinorganic field.

Alzheimer's Disease: Treatment Today and Tomorrow

Background and Aims

The scope of treatment in Alzheimer's Disease has widened in recent times with FDA approval of new drugs. This review looks at established treatments in AD as well as critically analyses the newer drugs available.

Methods

Data in this review was gathered from PubMed; Google Scholar and MEDLINE from January-March 2023. Search words used were 'Alzheimer's Disease treatment' and 'Dementia treatment'.

Results

Older time tested drugs like Acetyl Choline Receptor Inhibitors and NMDA Receptor antagonists remain the mainstay of pharmacological treatment in AD. Despite a lot of excitement about newer FDA approved drugs; we have to be cautious in their use. Aducanumab showed good reduction in CSF amyloid levels (biomarker of AD); but this did not necessarily translate into better clinical outcomes of patients.

Conclusion

Despite the recent advances and approval of drugs in treatment of AD, we have to exhibit caution while prescribing these drugs. Even with a sound mechanism of action, these drugs do not always show improvement in clinical outcomes. More clinical trials are required for development of drugs in treatment of AD which explore various different mechanisms of action.

Homocysteine-a retrospective and prospective appraisal

The biologically important amino acid homocysteine links sulfur, methionine, and one-carbon metabolism. This review describes its initial discovery, the identification of the clinical condition of "homocystinuria" and the recognition of its close relationship to folate and vitamin B12 metabolism. It discusses the history behind its current association with diverse diseases including neural tube defects, cardio- and cerebrovascular disease and, more recently, dementia and Alzheimer's Disease. It also explores current controversies and considers potential future research directions. It is intended to give a general overview of homocysteine in relation to health and disease.

Alzheimer's Disease Treatment: The Search for a Breakthrough

As the search for modalities to cure Alzheimer's disease (AD) has made slow progress, research has now turned to innovative pathways involving neural and peripheral inflammation and neuro-regeneration. Widely used AD treatments provide only symptomatic relief without changing the disease course. The recently FDA-approved anti-amyloid drugs, aducanumab and lecanemab, have demonstrated unclear real-world efficacy with a substantial side effect profile. Interest is growing in targeting the early stages of AD before irreversible pathologic changes so that cognitive function and neuronal viability can be preserved. Neuroinflammation is a fundamental feature of AD that involves complex relationships among cerebral immune cells and pro-inflammatory cytokines, which could be altered pharmacologically by AD therapy. Here, we provide an overview of the manipulations attempted in pre-clinical experiments. These include inhibition of microglial receptors, attenuation of inflammation and enhancement of toxin-clearing autophagy. In addition, modulation of the microbiome-brain-gut axis, dietary changes, and increased mental and physical exercise are under evaluation as ways to optimize brain health. As the scientific and medical communities work together, new solutions may be on the horizon to slow or halt AD progression.

Integrating Nutrient Biomarkers, Cognitive Function, and Structural MRI Data to Build Multivariate Phenotypes of Healthy Aging

BACKGROUND

Research in the emerging field of Nutritional Cognitive Neuroscience demonstrates that many aspects of nutrition - from entire diets to specific nutrients - affect cognitive performance and brain health.

OBJECTIVE

While prior research has primarily examined the bivariate relationship between nutrition and cognition, or nutrition and brain health, the present study sought to investigate the joint relationship between these essential and interactive elements of human health.

METHODS

We applied a state-of-the-art data fusion method, Coupled Matrix Tensor Factorization, to characterize the joint association between measures of nutrition (52 nutrient biomarkers), cognition (Wechsler Abbreviated Test of Intelligence and Wechsler Memory Scale), and brain health (high-resolution Magnetic Resonance Imaging measures of structural brain volume) within a cross-sectional sample of 111 healthy older adults that had an average age of 69.1 years, were 62% female and had an average Body Mass Index of 26.0.

RESULTS

Data fusion uncovered 3 latent factors that capture the joint association between specific nutrient profiles, cognitive measures, and cortical volumes, demonstrating the respects in which these health domains are coupled. Hierarchical cluster analysis further revealed systematic differences between the observed latent factors, providing evidence for multivariate phenotypes that represent high versus low levels of performance across multiple health domains. The primary features that distinguish between each phenotype were: (i) nutrient biomarkers for monounsaturated and polyunsaturated fatty acids; (ii) cognitive measures of immediate, auditory, and delayed memory; and (iii) brain volumes within frontal, temporal, and parietal cortex.

CONCLUSIONS

By incorporating innovations in nutritional epidemiology (nutrient biomarker analysis), cognitive neuroscience (high-resolution structural brain imaging), and statistics (data fusion), the present study provides an interdisciplinary synthesis of methods that elucidate how nutrition, cognition, and brain health are integrated through lifestyle choices that affect healthy aging.

Effectiveness of vitamin-B supplements on cognition in older adults: A meta-analysis

OBJECTIVES

We aimed to investigate the efficacy of B-vitamin and folic acid supplementation in slowing down cognitive function decline among older adults.

METHODS

We searched databases for trials comparing B-vitamin and folate supplementation versus placebo in older adults identified with or without impaired cognition.

RESULTS

23 articles were eligible and included in this meta-analysis. The mean difference (MD) in homocysteine levels was significant between the compared groups (MD:-4.52; 95%CI:-5.41 to 3.63, P < 0.001). However, the difference in the Mini-Mental State Examination (MMSE) was non-significant between the compared groups with or without cognitive impairment (MD:0.19; 95%CI: -0.148 to 0.531, P = 0.27), and (MD:0.04; 95%CI:-0.1 to 0.18, P = 0.59), respectively. The difference in Clinical Dementia Rating-sum of box (CDR-SOB) scores was non-significant (MD:-0.16; 95%CI:-0.49 to 0.18; P = 0.36).

CONCLUSIONS

B-vitamin and folate supplementations significantly reduced homocysteine levels. However, it failed to provide significant benefits over placebo in preventing or slowing the decline in cognitive function.

Recruitment across two decades of NIH-funded Alzheimer's disease clinical trials

BACKGROUND

Timely accrual of a representative sample is a key factor in whether Alzheimer's disease (AD) clinical trials successfully answer the scientific questions under study. Studies in other fields have observed that, over time, recruitment to trials has become increasingly reliant on larger numbers of sites, with declines in the average per-site recruitment rate. Here, we examined the trends in recruitment over a 20-year period of NIH-funded AD clinical trials conducted by the Alzheimer's Disease Cooperative Study (ADCS), a temporally consistent network of sites devoted to interventional research.

METHODS

We performed retrospective analyses of eleven ADCS randomized clinical trials. To examine the recruitment planning, we calculated the expected number of participants to be enrolled per site for each trial. To examine the actual trial recruitment rates, we quantified the number of participants enrolled per site per month.

RESULTS

No effects of time were observed on recruitment planning or overall recruitment rates across trials. No trial achieved an overall recruitment rate greater than one subject per site per month. We observed the fastest recruitment rates in trials with no competition and the slowest in trials that overlapped in time. The highest recruitment rates were consistently seen early within trials and declined over the course of studies.

CONCLUSIONS

Trial recruitment projections should plan for fewer than one participant randomized per site per month and consider the number of other AD trials being conducted concurrently.

Natural Bioactive Products as Epigenetic Modulators for Treating Neurodegenerative Disorders

Neurodegenerative disorders (NDDs) are major health issues in Western countries. Despite significant efforts, no effective therapeutics for NDDs exist. Several drugs that target epigenetic mechanisms (epidrugs) have been recently developed for the treatment of NDDs, and several of these are currently being tested in clinical trials. Furthermore, various bioproducts have shown important biological effects for the potential prevention and treatment of these disorders. Here, we review the use of natural products as epidrugs to treat NDDs in order to explore the epigenetic effects and benefits of functional foods and natural bioproducts on neurodegeneration.

Is Citicoline Effective in Preventing and Slowing Down Dementia?-A Systematic Review and a Meta-Analysis

BACKGROUND

Cognitive impairment is a staggering personal and societal burden; accordingly, there is a strong interest in potential strategies for its prevention and treatment. Nutritional supplements have been extensively investigated, and citicoline seems to be a promising agent; its role in clinical practice, however, has not been established. We systematically reviewed studies on the effect of citicoline on cognitive performance.

METHODS

We searched the PubMed and Cochrane Library databases for articles published between 2010 and 2022. Relevant information was extracted and presented following the PRISMA recommendations. Data were pooled using the inverse-variance method with random effects models.

RESULTS

We selected seven studies including patients with mild cognitive impairment, Alzheimer's disease or post-stroke dementia. All the studies showed a positive effect of citicoline on cognitive functions. Six studies could be included in the meta-analysis. Overall, citicoline improved cognitive status, with pooled standardized mean differences ranging from 0.56 (95% CI: 0.37-0.75) to 1.57 (95% CI: 0.77-2.37) in different sensitivity analyses. The overall quality of the studies was poor.

DISCUSSION

Available data indicate that citicoline has positive effects on cognitive function. The general quality of the studies, however, is poor with significant risk of bias in favor of the intervention. Other: PubMed and the Cochrane Library.

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.

Therapeutic Potential of Natural Compounds in Neurodegenerative Diseases: Insights from Clinical Trials

Neurodegenerative diseases are caused by the gradual loss of neurons' function. These neurological illnesses remain incurable, and current medicines only alleviate the symptoms. Given the social and economic burden caused by the rising frequency of neurodegenerative diseases, there is an urgent need for the development of appropriate therapeutics. Natural compounds are gaining popularity as alternatives to synthetic drugs due to their neuroprotective properties and higher biocompatibility. While natural compounds' therapeutic effects for neurodegenerative disease treatment have been investigated in numerous in vitro and in vivo studies, only few have moved to clinical trials. This article provides the first systematic review of the clinical trials evaluating natural compounds' safety and efficacy for the treatment of the five most prevalent neurodegenerative disorders: Alzheimer's disease, Parkinson's disease, multiple sclerosis, amyotrophic lateral sclerosis, and Huntington's disease.

Elevated Homocysteine Levels and Hypertension Relate to Cognitive Impairment via Increased White Matter Hyperintensity Volume

BACKGROUND

Recent studies have identified a relationship between elevated homocysteine levels and hypertension (HTN) with Alzheimer's disease (AD), but its pathogenesis remains unclear.

OBJECTIVE

To evaluate elevated homocysteine levels and HTN as risk factors for cognitive impairment (CI) and determine their relationship with white matter hyperintensity (WMH) volume.

METHODS

A total of 521 subjects were selected from the Alzheimer's Disease Neuroimaging Initiative (ADNI) database and divided into two groups according to the diagnostic criteria of the ADNI database. The CI group included 370 subjects, consisting of 122 with AD and 248 with mild CI, while the cognitively normal (CN) group contained 151 subjects. The history of HTN, homocysteine levels, WMH volume and Mini-Mental State Examination (MMSE) scores were analyzed.

RESULTS

The study found that patients with CI had higher homocysteine levels than those with CN. Additionally, WMH volume was significantly correlated with homocysteine levels in CI patients, and MMSE scores decreased as WMH volume increased. Further analysis revealed that CI patients with HTN had significantly higher homocysteine levels than those without HTN. Furthermore, the correlation between WMH volume and homocysteine levels was significant only in CI patients with HTN and not in those without HTN. In CN patients, there was no correlation between WMH volume and homocysteine levels in either the HTN or non-HTN groups, and no difference was observed in homocysteine levels.

CONCLUSIONS

It is indicated that elevated homocysteine levels in conjunction with HTN are associated with the increased volume of WMHs and CI.

Early Diagnosis of Alzheimer's Disease with Blood Test; Tempting but Challenging

The increasing prevalence of Alzheimer's disease (AD) has led to a health crisis. According to official statistics, more than 55 million people globally have AD or other types of dementia, making it the sixth leading cause of death. It is still difficult to diagnose AD and there is no definitive diagnosis yet; post-mortem autopsy is still the only definite method. Moreover, clinical manifestations occur very late in the course of disease progression; therefore, profound irreversible changes have already occurred when the disease manifests. Studies have shown that in the preclinical stage of AD, changes in some biomarkers are measurable prior to any neurological damage or other symptoms. Hence, creating a reliable, fast, and affordable method capable of detecting AD in early stage has attracted the most attention. Seeking clinically applicable, inexpensive, less invasive, and much more easily accessible biomarkers for early diagnosis of AD, blood-based biomarkers (BBBs) seem to be an ideal option. This review is an inclusive report of BBBs that have been shown to be altered in the course of AD progression. The aim of this report is to provide comprehensive insight into the research status of early detection of AD based on BBBs.

Age-Related Oxidative Redox and Metabolic Changes Precede Intraneuronal Amyloid-β Accumulation and Plaque Deposition in a Transgenic Alzheimer's Disease Mouse Model

BACKGROUND

Many identified mechanisms could be upstream of the prominent amyloid-β (Aβ) plaques in Alzheimer's disease (AD).

OBJECTIVE

To profile the progression of pathology in AD.

METHODS

We monitored metabolic signaling, redox stress, intraneuronal amyloid-β (iAβ) accumulation, and extracellular plaque deposition in the brains of 3xTg-AD mice across the lifespan.

RESULTS

Intracellular accumulation of aggregated Aβ in the CA1 pyramidal cells at 9 months preceded extracellular plaques that first presented in the CA1 at 16 months of age. In biochemical assays, brain glutathione (GSH) declined with age in both 3xTg-AD and non-transgenic controls, but the decline was accelerated in 3xTg-AD brains from 2 to 4 months. The decline in GSH correlated exponentially with the rise in iAβ. Integrated metabolic signaling as the ratio of phospho-Akt (pAkt) to total Akt (tAkt) in the PI3kinase and mTOR pathway declined at 6, 9, and 12 months, before rising at 16 and 20 months. These pAkt/tAkt ratios correlated with both iAβ and GSH levels in a U-shaped relationship. Selective vulnerability of age-related AD-genotype-specific pAkt changes was greatest in the CA1 pyramidal cell layer. To demonstrate redox causation, iAβ accumulation was lowered in cultured middle-age adult 3xTg-AD neurons by treatment of the oxidized redox state in the neurons with exogenous cysteine.

CONCLUSION

The order of pathologic progression in the 3xTg-AD mouse was loss of GSH (oxidative redox shift) followed by a pAkt/tAkt metabolic shift in CA1, iAβ accumulation in CA1, and extracellular Aβ deposition. Upstream targets may prove strategically more effective for therapy before irreversible changes.

The 677C > T variant in methylenetetrahydrofolate reductase causes morphological and functional cerebrovascular deficits in mice

Vascular contributions to cognitive impairment and dementia (VCID) particularly Alzheimer's disease and related dementias (ADRDs) are increasing; however, mechanisms driving cerebrovascular decline are poorly understood. Methylenetetrahydrofolate reductase (MTHFR) is a critical enzyme in the folate and methionine cycles. Variants in MTHFR, notably 677 C > T, are associated with dementias, but no mouse model existed to identify mechanisms by which MTHFR677C > T increases risk. Therefore, MODEL-AD created a novel knock-in (KI) strain carrying the Mthfr677C > T allele on the C57BL/6J background (Mthfr677C > T) to characterize morphology and function perturbed by the variant. Consistent with human clinical data, Mthfr677C > T mice have reduced enzyme activity in the liver and elevated plasma homocysteine levels. MTHFR enzyme activity is also reduced in the Mthfr677C > T brain. Mice showed reduced tissue perfusion in numerous brain regions by PET/CT as well as significantly reduced vascular density, pericyte number and increased GFAP-expressing astrocytes in frontal cortex. Electron microscopy revealed cerebrovascular damage including endothelial and pericyte apoptosis, reduced luminal size, and increased astrocyte and microglial presence in the microenvironment. Collectively, these data support a mechanism by which variations in MTHFR perturb cerebrovascular health laying the foundation to incorporate our new Mthfr677C > T mouse model in studies examining genetic susceptibility for cerebrovascular dysfunction in ADRDs.

Does folic acid supplementation have a positive effect on improving memory? A systematic review and meta-analysis of randomized controlled trials

Introduction

The results of randomized controlled trials (RCTs) on the effect of folic acid supplementation on memory status due to various heterogeneity, dosage, duration, and cognitive function assessments were inconclusive. Therefore, we have performed a systematic review and meta-analysis to investigate the effect of folic acid supplementation on memory in RCTs.

Method

Comprehensive computerized systematic searches were conducted throughout Scopus, PubMed/Medline, and Google Scholar from inception until February 2022 to investigate the effect of folic acid supplementation memory levels in RCTs. The standardized mean difference (SMD) and 95% confidence interval (CIs) were used to estimate the overall effect size using random-effects meta-analyses.

Results

The overall results of nine trials with 641 participants, revealed that folic acid supplementation did not significantly change memory score compared to placebo (SMD: 0.12; 95% CI: -0.17, 0.40, p = 0.418; I 2 = 62.6%). However, subgroup analyses showed that supplementation with folic acid had favorable effects on memory levels considering the following conditions: (1) doses lower than 1 mg/day, (2) treatment lasting more than 6 months, (3) conducted in eastern countries, and (4) in participants equal to or older than 70 years old. The dose-response analysis suggested a significant favorable effect on memory status at doses of 6-11 mg/d and a significant decline at doses of 17-20 mg/d.

Discussion

Although we did not find a significant effect of folic acid supplementation on memory, there were some suggestions of beneficial effects in the subgroup analyses.

Omics-based biomarkers discovery for Alzheimer's disease

Alzheimer's disease (AD) is the most common neurodegenerative disorders presenting with the pathological hallmarks of amyloid plaques and tau tangles. Over the past few years, great efforts have been made to explore reliable biomarkers of AD. High-throughput omics are a technology driven by multiple levels of unbiased data to detect the complex etiology of AD, and it provides us with new opportunities to better understand the pathophysiology of AD and thereby identify potential biomarkers. Through revealing the interaction networks between different molecular levels, the ultimate goal of multi-omics is to improve the diagnosis and treatment of AD. In this review, based on the current AD pathology and the current status of AD diagnostic biomarkers, we summarize how genomics, transcriptomics, proteomics and metabolomics are all conducing to the discovery of reliable AD biomarkers that could be developed and used in clinical AD management.

Incorporating historical control information in ANCOVA models using the meta-analytic-predictive approach

The meta-analytic-predictive (MAP) approach is a Bayesian meta-analytic method to synthesize and incorporate information from historical controls in the analysis of a new trial. Classically, only a single parameter, typically the intercept or rate, is assumed to vary across studies, which may not be realistic in more complex models. Analysis of covariance (ANCOVA) is often used to analyze trials with a pretest-posttest design, where both the intercept and the baseline effect (coefficient of the outcome at baseline) affect the estimated treatment effect. We extended the MAP approach to ANCOVA, to allow for variation in the intercept and the baseline effect across studies, and possibly also correlation between these parameters. The method was illustrated using data from the Alzheimer's Disease Cooperative Study (ADCS) and assessed with a simulation study. In the ADCS data, the proposed multivariate MAP approach yielded a prior effective sample size of 79 and 58 for the intercept and the baseline effect respectively and reduced the posterior standard deviation of the treatment effect by 12.6%. The result was robust to the choice of prior for the between-study variation. In the simulations, the proposed approach yielded power gains with a good control of the type I error rate. Ignoring the between-study correlation of the parameters or assuming no variation in the baseline effect generally led to less power gain. In conclusion, the MAP approach can be extended to a multivariate version for ANCOVA, which may improve the estimation of the treatment effect.

B Vitamin Supplementation Slows Cognitive Decline in Mild Cognitive Impairment Patients with Frontal Lobe Atrophy

BACKGROUND

The effects of B vitamins on mild cognitive impairment (MCI) patients' cognition have been mixed, suggesting the existence of moderating factors.

OBJECTIVE

A post hoc analysis of a negative B vitamin trial was performed to examine the potential modulating effect of regional brain atrophy on the cognitive response to B vitamins in MCI patients.

METHODS

In the 24-month randomized trial, 279 MCI outpatients took 500μ#x03BC;g methylcobalamin and 400μ#x03BC;g folic acid once per day or placebo tablets once per day. Sixty-four aspirin users were excluded from analysis as aspirin use has been found to have significant negative interaction effects. Subjects were followed up at months 12 and 24. The primary cognitive outcome was clinical dementia rating scale sum of boxes (CDR_SOB). In a subgroup of 83 subjects, MRI brain scans were performed at baseline to estimate regional brain atrophy ratios.

RESULTS

Among the trial subjects who had MRI data, B vitamin supplementation had no significant effect on CDR_SOB, despite having significant homocysteine lowering effects. The atrophy ratio of the left frontal lobe significantly moderated the effect of B vitamin supplementation on CDR_SOB, after adjusting for confounders, in that B vitamin supplementation was associated with lower CDR_SOB scores (i.e., better cognitive function) at the 24th month among those patients with above median atrophy ratios, but not among those with lower atrophy ratios, in the left frontal lobe.

CONCLUSION

B vitamins may be more effective in slowing down cognitive decline in MCI patients with atrophy in the left frontal lobe.

Complementary and Integrative Medicine for Neurocognitive Disorders and Caregiver Health

PURPOSE OF REVIEW

Integrative medicine is the practice of combining conventional medical treatments with "alternative" or "complementary" therapies. Integrative psychiatry is a holistic, person-centered approach to neuropsychiatric disorders that emphasizes a person's physical, emotional, interpersonal, behavioral, nutritional, environmental, and spiritual dimensions to achieve well-being. Older adults are more prone to physical injury, interpersonal loss, chronic illnesses, and physical and cognitive decline that can manifest as anxiety, depression, with functional decline and inability to care for self. Additionally, stress of caring for older adults with dementia can adversely affect caregivers' health. Although integrative approaches are perceived as safer and less stigmatizing, it is important to understand the risks and benefits of such therapies for older adults with neurocognitive disorders and their caregivers.

RECENT FINDINGS

Here, we summarize the results of the recent clinical trials and meta-analyses that provide evidence for integrative approaches to treating older adults with cognitive disorders and their caregivers which include the use of diet and supplements, and mind-body therapies. Dietary and mind-body therapies have become increasingly popular and show the strongest evidence of effectiveness for cognitive disorders and caregiver stress. Vitamins and supplements are the most popular integrative intervention, but there is mixed evidence supporting their use and the concern for herb (supplement)-drug interactions. While there is increasing popularity of integrative treatments, information to guide clinicians providing care for older adults remains limited, with variable scientific rigor of the available RCTs for a large number of commonly used integrative interventions particularly for cognitive disorders and caregiver stress and well-being.

Ketones: potential to achieve brain energy rescue and sustain cognitive health during ageing

Alzheimer’s disease (AD) is the most common major neurocognitive disorder of ageing. Although largely ignored until about a decade ago, accumulating evidence suggests that deteriorating brain energy metabolism plays a key role in the development and/or progression of AD-associated cognitive decline. Brain glucose hypometabolism is a well-established biomarker in AD but was mostly assumed to be a consequence of neuronal dysfunction and death. However, its presence in cognitively asymptomatic populations at higher risk of AD strongly suggests that it is actually a pre-symptomatic component in the development of AD. The question then arises as to whether progressive AD-related cognitive decline could be prevented or slowed down by correcting or bypassing this progressive ‘brain energy gap’. In this review, we provide an overview of research on brain glucose and ketone metabolism in AD and its prodromal condition – mild cognitive impairment (MCI) – to provide a clearer basis for proposing keto-therapeutics as a strategy for brain energy rescue in AD. We also discuss studies using ketogenic interventions and their impact on plasma ketone levels, brain energetics and cognitive performance in MCI and AD. Given that exercise has several overlapping metabolic effects with ketones, we propose that in combination these two approaches might be synergistic for brain health during ageing. As cause-and-effect relationships between the different hallmarks of AD are emerging, further research efforts should focus on optimising the efficacy, acceptability and accessibility of keto-therapeutics in AD and populations at risk of AD.

Homocysteine is related to enlarged perivascular spaces in the brainstem in patients with isolated pontine infarction

Background

Homocysteine is correlated with several imaging features of cerebral small vessel disease including white matter hyperintensities, lacunes, and enlarged perivascular spaces (EPVS) in the basal ganglia. However, little is known about EPVS in the brainstem. This study aimed to investigate the correlation between serum total homocysteine (tHcy) and EPVS in the brainstem in patients with acute isolated pontine infarction.

Methods

Consecutive patients with isolated pontine infarction were retrospectively enrolled. Clinical characteristics and laboratory tests including tHcy were recorded. Imaging markers of cerebral small vessel disease including EPVS in the basal ganglia (BG-EPVS), EPVS in the centrum semiovale, and EPVS in the midbrain or pons (brainstem-EPVS) were assessed using conventional magnetic resonance imaging. The relation between tHcy and EPVS of different parts in the brain was analyzed using univariate and multivariate regression model.

Results

A total of 227 patients were included (mean age 67.10 ± 9.38 years, male sex 58.6%). The frequencies of brainstem-EPVS and moderate to severe BG-EPVS accounted for 40.1% (91/227) and 40.5% (92/227) respectively. After controlling for confounding factors, multivariate logistic regression analyses showed that tHcy was an independent risk factor for both moderate to severe BG-EPVS (P = 0.003, P for trend < 0.001) and the presence of brainstem-EPVS (P < 0.001, P for trend < 0.001) in a dose-dependent manner. Furthermore, multivariate linear regression model indicated that the presence of brainstem-EPVS (β = 0.264, 95% confidence interval = 0.143-0.402, P < 0.001) and the severity of BG-EPVS (β = 0.162, 95% confidence interval = 0.024-0.197, P = 0.013) were positively associated with serum tHcy.

Conclusions

Serum tHcy is correlated with brainstem-EPVS and BG-EPVS dose-dependently. This study may support a contributing role for homocysteine in the pathophysiology of EPVS in the brainstem and the basal ganglia.

The role of mixed B vitamin intakes on cognitive performance: Modeling, genes and miRNAs involved

OBJECTIVE

To assess the relationships between mixed B vitamin intakes (B1, B2, B3, B6, B9, B12) and cognitive performance, as well as their molecular mechanisms.

METHODS

The associations of mixed B vitamin intakes with cognitive function were assessed using multivariate regression models, weighted quantile sum (WQS), quantile g-computation (qgcomp), and Bayesian kernel machine regression (BKMR). GeneMANIA, Comparative Toxicogenomics Database, MIENTURNET, miRNAsong were employed as the main data-mining methods.

RESULTS

Overall effects of the B vitamin intake mixture were significantly associated with global cognition in the WQS, qgcomp, and BKMR models. A mixture of B vitamins (B1, B2, B3, B9) interacted with the five genes (IL1B, BCL2, CASP3, BAX, PTGS2) and was associated with better cognitive function, especially CASP3 and BAX. Physical interactions (77.6%) were observed to be the most important interactions in gene networks. The IL-18 signaling pathway, apoptosis, and Alzheimer's disease were annotated as the key molecular mechanisms involved in mixed B vitamins' improving cognitive function. NFKB1, ATF3, and NR3C1 were the key significant transcription factors associated with cognitive function targeted by a mixture of B vitamins. The strong interaction and expression of hsa-miR-34a-5p, hsa-miR-128-3p, hsa-miR-181a-5p, and hsa-miR-204-5p are involved in mixed B vitamins' better cognitive performance. We also created and evaluated miRNA sponge sequences for these miRNAs, which might be used to alleviate cognitive decline. The cutoff thresholds for B vitamin intake levels that are associated with cognition performance were reported.

CONCLUSIONS

Given the increased incidence of dementia across the world, increasing daily mixed B vitamin intake via regular meals may contribute to minimizing dementia risk. Further studies are warranted to identify these links in well-characterized cohorts of diverse populations, either independently or together.

Are micronutrient levels and supplements causally associated with the risk of Alzheimer's disease? A two-sample Mendelian randomization analysis

The potential of micronutrients, including vitamins and minerals, to prevent Alzheimer's disease (AD) has attracted much attention. However, the causal associations between micronutrient levels or supplements and AD risk remain unclear. We performed a two-sample Mendelian randomization (2SMR) analysis to evaluate the causal associations between micronutrient levels and supplements and AD risk. A total of 60 genome-wide association studies (GWAS) related to five types of vitamins (vitamins A, B, C, D, and E) and seven types of minerals (magnesium, calcium, iron, copper, zinc, selenium, and phosphorus) were included. For vitamins, using the data source provided by two GWAS, the analysis of 2SMR indicated that the vitamin D level was causally associated with a decreased risk of AD (IVW, OR: 0.474, 95%CI: 0.269-0.834, P-value = 0.010; OR: 0.857, 95%CI: 0.748-0.982, P-value = 0.027), while no effect of vitamin D supplement was observed. Currently, available data do not support the causal associations between the other four types of vitamins/supplements and AD risk. As for minerals, the copper level acted as a causal protective factor for AD risk (IVW, OR: 0.865, 95%CI: 0.751-0.998, P-value = 0.046). In conclusion, the present analysis indicated that among the vitamins and minerals, vitamin D and copper levels exhibited negative causal associations with AD risk, which may help in better use of micronutrients to prevent AD and require further verification by further studies.

Vitamin B12 as a Cholinergic System Modulator and Blood Brain Barrier Integrity Restorer in Alzheimer's Disease

So far, the cholinergic hypothesis of Alzheimer's disease (AD) remains the fundamental explanation for the complex etiopathology of AD. However, therapeutics raising synaptic acetylcholine (Ach) or having cholinergic receptors agonistic activity had shown limited clinical efficacy, possibly, due to lacking capability to aggregate cholinergic receptors within the degenerated cholinergic neurons. Vitamin-B12 (B12) is an epigenetic modifier. It has a specific CNS transport system via the cubam receptors. The later enclose a cholinergic aggregator; agrin protein, suggesting that B12 administration may cause cholinergic receptors aggregation. Further, B12 involvement in homocysteine (Hcy) metabolism may restore blood brain barrier (BBB) integrity disrupted by elevated Hcy levels in AD. Here in, using a pharmacological model of cholinergic amnesia, three different B12 doses were compared to the standard of care; donepezil (DON) regarding cholinergic system modulation, and Hcy metabolic pathways. Further, AD-associated cerebro-vascular pathology was assessed by morphometric analyses of cerebro-vasculature morphology and ultrastructure using scanning and transmission electron-microscopes, respectively. Consequent effect on key AD-hallmarks and behavioral cognitive tests was also examined. The highest B12-tested dose (B12-HD) showed the greatest hippocampal cholinergic modulation with dose-dependent preferential upregulation of one cholinergic receptor over the other. Altered Hcy metabolism was proved to be a consequence of cholinergic disruption that was variably reversed by different B12 doses. In spite of equipotent effect of DON and B12-HD therapies in decreasing β-amyloid synthesis, B12-HD-treated group revealed the greatest restoration of BBB integrity indicating superior capability of β-amyloid clearance. Therefore, B12-HD therapy may represent a promising AD-modifying agent with extra-ability over conventional cholinergic modulators to aggregate cholinergic receptors.

Reversal of Lipid Metabolism Dysregulation by Selenium and Folic Acid Co-Supplementation to Mitigate Pathology in Alzheimer’s Disease

Aberrant lipid metabolism is reported to be closely related to the pathogenesis of neurodegenerative diseases, such as Alzheimer’s disease (AD). Selenium (Se) and folate are two ideal and safe nutritional supplements, whose biological effects include regulating redox and homocysteine (Hcy) homeostasis in vivo. Here, to achieve effective multitarget therapy for AD, we combined Se and folic acid in a co-supplementation regimen (Se-FA) to study the therapeutic potential and exact mechanism in two transgenic mouse models of AD (APP/Tau/PSEN and APP/PS1). In addition to a reduction in Aβ generation and tau hyperphosphorylation, a restoration of synaptic plasticity and cognitive ability was observed in AD mice upon Se-FA administration. Importantly, by using untargeted metabolomics, we found that these improvements were dependent on the modulation of brain lipid metabolism, which may be associated with an antioxidant effect and the promotion of Hcy metabolism. Thus, from mechanism to effects, this study systematically investigated Se-FA as an intervention for AD, providing important mechanistic insights to inform its potential use in clinical trials.

Combined homocysteine and apoE rs429358 and rs7412 polymorphism in association with serum lipid levels and cognition in Chinese community-dwelling older adults

BACKGROUND

ApoE gene polymorphism and serum total homocysteine (tHcy) has been reportedly associated with cognition. In this study, we assessed the association of combined ApoE gene polymorphism and tHcy with cognition in Chinese elder adults.

METHODS

A cross- sectional study was carried out by recruiting 1458 community-dwelling people aged 55+ and above in Beijing in 2009. All participants were interviewed using a standard questionnaire and underwent a physical examination. The mini-mental scale examination (MMSE) score was used in assessing cognitive function. Fasting venous blood samples were taken for ApoE rs429358, rs7412 genotyping, tHcy and other serum lipid measurements.

RESULTS

Participants with high serum tHcy level showed a relatively lower orientation, attention abilities as well as the total MMSE score than the group with normal tHcy after adjusting confounding factors. ApoE rs429358 and rs7412 variants were observed to have the highest serum TC and TG level in the subjects with high serum tHcy level (p <  0.05). Cognition of the subjects was found to be significantly associated with high serum tHcy level and ApoE genetic polymorphism (p <  0.05). Independent of age, BMI, education levels, smoking and alcohol drinking, the worst cognitive ability were detected in the high serum tHcy level subjects with ApoE rs429358C/T and rs7412 C/T as compare with other groups, especially orientation function, memory and delayed recall ability and attention ability.

CONCLUSION

High serum tHcy level in combination with ApoE rs429358 and rs7412 variants might be linked with serum lipid levels and cognition, particularly for orientation function and memory and delayed recall ability in old Chinese adults.

Association Between Blood Biochemical Factors Contributing to Cognitive Decline and B Vitamins in Patients With Alzheimer's Disease

Background

Malnutrition, metabolism stress, inflammation, peripheral organs dysfunction, and B vitamins deficiency significantly contribute to the progression and mortality of Alzheimer's disease (AD). However, it is unclear which blood biochemical indicators are most closely related to cognitive decline and B vitamins deficiency (thiamine, folate, vitamin B12) in patients with AD.

Methods

This was a cross-sectional study of 206 AD patients recruited from six hospitals in China. Thiamine diphosphate (TDP), the bioactive form of thiamine, was measured by high-performance liquid chromatography fluoroscopy (HPLC) at a single center. Levels of biochemical indicators (except TDP) were measured by regular and standard laboratory tests in each hospital. Pearson's rank correlation analysis was used to assess relationships between B vitamins and biochemical indicators. T-test was used to compare the difference between ApoE ε4 and non-ApoE ε4 groups. Differences were considered statistically significant as P < 0.05.

Results

Among the biochemical results, in AD population, malnutrition indicators (erythrocyte, hemoglobin, serum albumin, and total protein) were most significantly associated with cognitive function, as was free triiodothyronine (FT3) levels which had been observed in previous study. Malnutrition and FT3 levels depend on age but not apolipoprotein E (ApoE) genotype. Meanwhile, Among the B vitamins, TDP was the most significantly associated with malnutrition indicators and FT3.

Conclusion

Our results indicated that TDP reduction could be a modifiable risk factor for malnutrition and FT3 that contributed to cognitive decline in AD patients. Correcting thiamine metabolism could serve as an optional therapy target for AD treatment.