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.

Hyperhomocysteinemia in Adult Patients: A Treatable Metabolic Condition

Hyperhomocysteinemia (HHcy) is recognized as an independent risk factor for various significant medical conditions, yet controversy persists around its assessment and management. The diagnosis of disorders afffecting homocysteine (Hcy) metabolism faces delays due to insufficient awareness of its clinical presentation and unique biochemical characteristics. In cases of arterial or venous thrombotic vascular events, particularly with other comorbidities, it is crucial to consider moderate to severe HHcy. A nutritional approach to HHcy management involves implementing dietary strategies and targeted supplementation, emphasizing key nutrients like vitamin B6, B12, and folate that are crucial for Hcy conversion. Adequate intake of these vitamins, along with betaine supplementation, supports Hcy remethylation. Lifestyle modifications, such as smoking cessation and regular physical activity, complement the nutritional approach to enhance Hcy metabolism. For individuals with HHcy, maintaining a plasma Hcy concentration below 50 μmol/L consistently is vital to lowering the risk of vascular events. Collaboration with healthcare professionals and dietitians is essential for developing personalized dietary plans addressing the specific needs and underlying health conditions. This integrated approach aims to optimize metabolic processes and reduce the associated health risks.

A Systematic Review of Dietary Supplements in Alzheimer's Disease

Alzheimer's is the most common neurodegenerative disease among the aging population, which has been a major global challenge. The pathogenesis of the disease is still undetermined but postulated to be involved in various mechanisms including oxidative stress, excitotoxicity, inflammation, cell death, genetic factors, protein accumulation, and degradation. There are few Food and Drug Administration (FDA)-approved drugs available for the treatment of Alzheimer's disease (AD) that have limited benefits along with associated adverse effects. A retrospective review of randomized double-blind controlled trials of various supplements used in AD patients was performed on a PubMed search from January 1983 to March 2022. We found 10 articles that have shown positive outcomes in various cognitive domains. We conclude that there should be a global standard to endorse the quality and safety of these supplements.

B-vitamins and homocysteine as determinants of bone health: a literature review of human studies

Although there are several factors related to bone diseases such as physical activity, gender (oestrogen), race/ethnicity, smoking and alcohol habits, nutrition is a modifiable risk factor that could be employed to prevent or manage the onset of bone health diseases such as osteoporosis in humans. Aside from calcium and vitamin D, B-vitamins are a group of water-soluble vitamins that play a vital role in cell metabolism. In this review, current evidence on B-vitamins and bone health was assessed. Clinical trials (interventions) indicated that treatment with B-vitamins impact the concentrations of total plasma/serum homocysteine concentrations (tHcy), however, most studies reported a lack of an effect of low homocysteine concentrations on bone turnover markers, bone mineral density (BMD) or fracture risks. Current studies have been inconsistent in their reports on the role of B-vitamins and homocysteine in bone health. More data are therefore required to show the mechanism and effect of tHcy and B-vitamins on BMD, bone metabolism and fracture risk. This article is protected by copyright. All rights reserved.

Safety, Tolerability, Pharmacokinetics and Initial Pharmacodynamics of a Subcommissural Organ-Spondin-Derived Peptide: A Randomized, Placebo-Controlled, Double-Blind, Single Ascending Dose First-in-Human Study

INTRODUCTION

This randomized, double-blind, placebo-controlled study in healthy volunteers assessed the safety, tolerability, and pharmacokinetics of single ascending doses of intravenously administered NX210-a linear peptide derived from subcommissural organ-spondin-and explored the effects on blood/urine biomarkers and cerebral activity.

METHODS

Participants in five cohorts (n = 8 each) were randomized to receive a single intravenous dose of NX210 (n = 6 each) (0.4, 1.25, 2.5, 5, and 10 mg/kg) or placebo (n = 2 each); in total, 10 and 29 participants received placebo and NX210, respectively. Blood samples were collected for pharmacokinetics within 180 min post dosing. Plasma and urine were collected from participants (cohorts: 2.5, 5, and 10 mg/kg) for biomarker analysis and electroencephalography (EEG) recordings within 48 h post dosing. Safety/tolerability and pharmacokinetic data were assessed before ascending to the next dose.

RESULTS

The study included 39 participants. All dosages were safe and well tolerated. All treatment-emergent adverse events (n = 17) were of mild severity and resolved spontaneously (except one with unknown outcome). Twelve treatment-emergent adverse events (70.6%) were deemed drug related; seven of those (58.3%) concerned nervous system disorders (dizziness, headache, and somnolence). The pharmacokinetic analysis indicated a short half-life in plasma (6-20 min), high apparent volume of distribution (1870-4120 L), and rapid clearance (7440-16,400 L/h). In plasma, tryptophan and homocysteine showed dose-related increase and decrease, respectively. No drug dose effect was found for the glutamate or glutamine plasma biomarkers. Nevertheless, decreased blood glutamate and increased glutamine were observed in participants treated with NX210 versus placebo. EEG showed a statistically significant decrease in beta and gamma bands and a dose-dependent increasing trend in alpha bands. Pharmacodynamics effects were sustained for several hours (plasma) or 48 h (urine and EEG).

CONCLUSION

NX210 is safe and well tolerated and may exert beneficial effects on the central nervous system, particularly in terms of cognitive processing.

Dementia in Africa: Current evidence, knowledge gaps, and future directions

In tandem with the ever-increasing aging population in low and middle-income countries, the burden of dementia is rising on the African continent. Dementia prevalence varies from 2.3% to 20.0% and incidence rates are 13.3 per 1000 person-years with increasing mortality in parts of rapidly transforming Africa. Differences in nutrition, cardiovascular factors, comorbidities, infections, mortality, and detection likely contribute to lower incidence. Alzheimer's disease, vascular dementia, and human immunodeficiency virus/acquired immunodeficiency syndrome-associated neurocognitive disorders are the most common dementia subtypes. Comprehensive longitudinal studies with robust methodology and regional coverage would provide more reliable information. The apolipoprotein E (APOE) ε4 allele is most studied but has shown differential effects within African ancestry compared to Caucasian. More candidate gene and genome-wide association studies are needed to relate to dementia phenotypes. Validated culture-sensitive cognitive tools not influenced by education and language differences are critically needed for implementation across multidisciplinary groupings such as the proposed African Dementia Consortium.

Blood and CSF Homocysteine Levels in Alzheimer's Disease: A Meta-Analysis and Meta-Regression of Case-Control Studies

OBJECTIVE

Hyperhomocysteinemia (HHcy), as an important risk factor for Alzheimer's disease (AD), would aggravate cognitive dysfunction. This study aimed to investigate whether and to what degree the homocysteine (Hcy) levels in blood and cerebrospinal fluid (CSF) were elevated in AD patients compared with healthy controls and to explore the factors related to the elevated Hcy levels in AD patients.

METHODS

PubMed and Embase databases were searched to identify eligible studies, and study quality was evaluated using the Newcastle-Ottawa Quality Assessment Scale. Ratio of mean (RoM) Hcy concentrations was used as a measure of fold-change between AD patients and healthy control subjects.

RESULTS

We identified 35 eligible studies, consisting a total of 2172 patients with AD and 2289 healthy controls. The pooled results showed that patients with AD had a significantly higher blood level of Hcy (RoM, 1.32; 95% CI, 1.25-1.40; p<0.001) than controls did, with large heterogeneity across studies (I²=81.4%, p<0.001). Hcy level in CSF did not differ significantly between patients with AD than controls (RoM, 1.12; 95% CI, 0.90-1.39, p=0.293; I²=69.4%, p=0.02). A random effects meta-regression analysis revealed that there was an inverse correlation between the blood levels of Hcy and folate (p=0.006). There was no link found between the blood levels of vitamin B_12, or the Mini-Mental Status Examination scores reflecting the degree of cognitive impairment, and blood levels of Hcy.

CONCLUSION

Regardless of dementia severity, there is an approximate one-third increase in blood Hcy in AD patients, which is robustly associated with a decreased level of blood folate in AD, but not with that of blood vitamin B₁₂ nor the degree of dementia. Future investigation on the cause-and-effect link between Hcy and folate is warranted to clarify this issue.

Impact of nanodisc lipid composition on cell-free expression of proton-coupled folate transporter

The Proton-Coupled Folate Transporter (PCFT) is a transmembrane transport protein that controls the absorption of dietary folates in the small intestine. PCFT also mediates uptake of chemotherapeutically used antifolates into tumor cells. PCFT has been identified within lipid rafts observed in phospholipid bilayers of plasma membranes, a micro environment that is altered in tumor cells. The present study aimed at investigating the impact of different lipids within Lipid-protein nanodiscs (LPNs), discoidal lipid structures stabilized by membrane scaffold proteins, to yield soluble PCFT expression in an E. coli lysate-based cell-free transcription/translation system. In the absence of detergents or lipids, we observed PCFT quantitatively as precipitate in this system. We then explored the ability of LPNs to support solubilized PCFT expression when present during in-vitro translation. LPNs consisted of either dimyristoyl phosphatidylcholine (DMPC), palmitoyl-oleoyl phosphatidylcholine (POPC), or dimyristoyl phosphatidylglycerol (DMPG). While POPC did not lead to soluble PCFT expression, both DMPG and DMPC supported PCFT translation directly into LPNs, the latter in a concentration dependent manner. The results obtained through this study provide insights into the lipid preferences of PCFT. Membrane-embedded or solubilized PCFT will enable further studies with diverse biophysical approaches to enhance the understanding of the structure and molecular mechanism of folate transport through PCFT.

B vitamins and prevention of cognitive decline and incident dementia: a systematic review and meta-analysis

CONTEXT

Elevation of homocysteine (Hcy) levels is well-established as a risk factor for dementia, yet controversy exists regarding whether B-vitamin-mediated reduction of homocysteine levels can benefit cognitive function.

OBJECTIVE

To investigate whether B vitamin supplementation can reduce the risk of cognitive decline and incident dementia.

DATA SOURCES

The PubMed, EMBASE, Cochrane Library, and Web of Science were systematically searched for articles published from the inception dates to March 1, 2020. Randomized controlled trials (RCT) were included if B vitamins were supplied to investigate their effect on the rate of cognitive decline. Cohort studies investigating dietary intake of B vitamins and the risk of incident dementia were eligible. Cross-sectional studies comparing differences in levels of B vitamins and Hcy were included.

DATA EXTRACTION

Two reviewers independently performed data extraction and assessed the study quality.

DATA ANALYSIS

Random-effect or fixed-effect models, depending on the degree of heterogeneity, were performed to calculate mean differences (MDs), hazard ratios (HRs), and odds ratios (ORs).

RESULTS

A total of 95 studies with 46175 participants (25 RCTs, 20 cohort studies, and 50 cross-sectional studies) were included in this meta-analysis. This meta-analysis supports that B vitamins can benefit cognitive function as measured by Mini-Mental State Examination score changes (6155 participants; MD, 0.14, 95%CI 0.04 to 0.23), and this result was also significant in studies where placebo groups developed cognitive decline (4211 participants; MD, 0.16, 95%CI 0.05 to 0.26), suggesting that B vitamins slow cognitive decline. For the > 12 months interventional period stratum, B vitamin supplementation decreased cognitive decline (3814 participants; MD, 0.15, 95%CI 0.05 to 0.26) compared to placebo; no such outcome was detected for the shorter interventional stratum (806 participants; MD, 0.18, 95%CI -0.25 to 0.61). In the non-dementia population, B vitamin supplementation slowed cognitive decline (3431 participants; MD, 0.15, 95%CI 0.04 to 0.25) compared to placebo; this outcome was not found for the dementia population (642 participants; MD, 0.20, 95%CI -0.35 to 0.75). Lower folate levels (but not B12 or B6 deficiency) and higher Hcy levels were significantly associated with higher risks of dementia (folate: 6654 participants; OR, 1.76, 95%CI 1.24 to 2.50; Hcy: 12665 participants; OR, 2.09, 95%CI 1.60 to 2.74) and cognitive decline (folate: 4336 participants; OR, 1.26, 95%CI 1.02 to 1.55; Hcy: 6149 participants; OR, 1.19, 95%CI 1.05 to 1.34). Among the population without dementia aged 50 years and above, the risk of incident dementia was significantly decreased among individuals with higher intake of folate (13529 participants; HR, 0.61, 95%CI 0.47 to 0.78), whereas higher intake of B12 or B6 was not associated with lower dementia risk.

CONCLUSIONS

This meta-analysis suggests that B vitamin supplementation is associated with slowing of cognitive decline, especially in populations who received early intervention and intervention of long duration; the study also indicates that higher intake of dietary folate, but not B12 or B6, is associated with a reduced risk of incident dementia in non-dementia aged population. Given the prevalence of dementia cases in many countries with aging populations, public health policies should be introduced to ensure that subgroups of the population at risk have an adequate B vitamin status.

Changes in Biothiol Levels Are Closely Associated with Alzheimer's Disease

BACKGROUND

Serum homocysteine (Hcy) level is considered to be an important biomarker for Alzheimer's disease (AD); however, the status of Hcy in brain tissue, and the association between brain and serum levels of Hcy in AD patients remain unclear.

OBJECTIVE

We aimed to examine whether the changes of three thiols are consistent in serum of AD patients and the brain of APP/PS1 mice, and to verify the effectiveness of Hcy as a biomarker for early AD detection.

METHODS

The levels of Hcy, cysteine (Cys), and glutathione (GSH) in Aβ1-42-treated PC12 cells, the brain and hippocampus of APP/PS1 mouse, and the serum of AD patients were evaluated using ethyl (E)-3-(9-chloro-11-oxo-2,3,6,7-tetrahydro-1H,5H,11H-pyrano[2,3-f] pyrido [3,2,1 -ij] quinolin-10-yl)-2-cyanoacrylate (Probe 1) and ELISA assay or LC-MS.

RESULTS

Measurement by Probe 1 revealed a significant increase in Hcy level, and a decrease in Cys and GSH levels in Aβ1-42-treated PC12 cells and the serum of AD patients. The hippocampus and whole brain of APP/PS1 mice also showed a significant increase in Hcy level alongside the accumulation of age-related AD symptoms. The upregulation of Hcy and the downregulation of Cys and GSH were reversed in the Aβ1-42-treated PC12 cells and the brain of APP/PS1 mice when supplemented with VB6.

CONCLUSION

Changes in Hcy, Cys, and GSH levels in the brain of APP/PS1 mice and Aβ1-42-treated PC12 cells were observed in situ with a new fluorescent probe, which were consistent with the abnormal changes in Hcy, Cys, and GSH levels in the serum of AD patients. VB6 supplementation was successful in ameliorating abnormal increases in Hcy levels.

Homocysteine and Folic Acid: Risk Factors for Alzheimer's Disease-An Updated Meta-Analysis

Background: Recent studies have reported that homocysteine (Hcy) may play a vital role in the pathogenesis of vascular dementia (VaD) and Alzheimer's disease (AD). Our study explored the relationship between the plasma Hcy and folate levels and the risk of dementia.

Methods: We searched Embase, PubMed, and Web of Science for published literature, including case-control studies and prospective cohort studies, and performed a systematic analysis.

Results: The results of our meta-analysis, consisting of case-control studies, showed higher levels of Hcy and lower levels of folate in dementia, AD, and VaD patients than those in non-demented controls (for dementia: SMD = 0.812, 95% CI [0.689, 0.936], p = 0.000 for Hcy; SMD = −0.677, 95% CI [−0.828, −0.525], p = 0.000 for folate). AD patients showed significantly lower plasma Hcy levels compared to VaD patients (SMD = −0.278, 95% CI [−0.466, −0.09], p = 0.000). Subgroup analysis revealed that ethnicity, average age, and dementia type had no significant effect on this association. Furthermore, from the analysis of prospective cohort studies, we identified that elevated plasma Hcy levels were associated with an increased risk of dementia, AD, and VaD (RR_dementia = 1.22, 95% CI [1.08, 1.36]; RR_AD = 1.07, 95% CI [1.04, 1.11]; RR_VaD = 1.13, 95% CI [1.04, 1.23]). In addition, every 5 μmol/L increase in the plasma Hcy level was associated with a 9% increased risk of dementia and a 12% increased risk of AD.

Conclusion: Hcy and folic acid are potential predictors of the occurrence and development of AD. A better understanding of their function in dementia could provide evidence for clinicians to rationalize clinical intervention strategies.

Good, better, best: clinical scenarios for the use of L-methylfolate in patients with MDD

Depression is among the most prevalent mental disorders worldwide, and a substantial proportion of patients do not respond adequately to standard antidepressants. Our understanding of the pathophysiology of depression is no longer limited to the chemical imbalance of neurotransmitters, but also involves the interplay of proinflammatory modulators in the central nervous system, as well as folate metabolism. Additional factors such as stress and metabolic disorders also may contribute. Multiple inflammatory, metabolic, and genetic markers have been identified and may provide critical information to help clinicians individualize treatments for patients to achieve optimal outcomes. Recent advancements in research have clarified underlying causes of depression and have led to possible new avenues for adjunctive treatment. Among these is L-methylfolate, a medical food that is thought to enhance synthesis of monoamines (serotonin, norepinephrine, and dopamine), suppress inflammation, and promote neural health. Clinical studies that assessed supplemental use of L-methylfolate in patients with usual care-resistant depression found that it resulted in improved outcomes. Patients with selective serotonin reuptake inhibitor-resistant depression, and particularly subgroups with biomarkers of inflammation or metabolic disorders or folate metabolism-related genetic polymorphisms (or ≥2 of these factors), had the best responses. Considering this, the goals of this review are to 1) highlight recent advances in the pathophysiology of major depressive disorder as it pertains to folate and associated biomarkers and 2) establish the profiles of patients with depression who could benefit most from supplemental use of L-methylfolate.

Targeted metabolomics study of early pathological features in hippocampus of triple transgenic Alzheimer's disease male mice

Alzheimer's disease (AD) is a serious neurodegenerative disease in people of age 65 or above. The detailed etiology and pathogenesis of AD have not been elucidated yet. In this study, the hippocampi of 2- and 6-month-old triple transgenic Alzheimer's disease male mice and age-sex-matched wild-type (WT) mice were analyzed by using targeted metabolomics approach. Compared with WT mice, 24 and 60 metabolites were found with significant differences in 2- and 6-month-old AD mice. Among these, 14 metabolites were found common while 10 metabolites showed consistent variable trends in both groups. These differential metabolites are found associated with amino acid, lipid, vitamin, nucleotide-related base, neurotransmitter and energy metabolisms, and oxidative stress. The results suggest that these differential metabolites might play a critical role in AD pathophysiology, and may serve as potential biomarkers for AD. Moreover, the results highlight the involvement of abnormal purine, pyrimidine, arginine, and proline metabolism, along with glycerophospholipid metabolism in early pathology of AD. For the first time, several differential metabolites are found to be associated with AD in this study. Targeted metabolomics can be used for rapid and accurate quantitative analysis of specific target metabolites associated with AD.

Emerging Concepts in Nutrient Needs

Dietary reference intakes (DRIs) are quantitative, nutrient intake-based standards used for assessing the diets and specific nutrient intakes of healthy individuals and populations and for informing national nutrition policy and nutrition programs. Because nutrition needs vary by age, sex, and physiological state, DRIs are often specified for healthy subgroups within a population. Diet is known to be the leading modifiable risk factor for chronic disease, and the prevalence of chronic disease is growing in all populations globally and across all subgroups, but especially in older adults. It is known that nutrient needs can change in some chronic disease and other clinical states. Disease states and/or disease treatment can cause whole-body or tissue-specific nutrient depletion or excess, resulting in the need for altered nutrient intakes. In other cases, disease-related biochemical dysfunction can result in a requirement for a nonessential nutrient, rendering it as conditionally essential, or result in toxicity for a food component at levels usually tolerated by healthy people, as seen in inborn errors of metabolism. Here we summarize examples from a growing body of literature of disease-altering nutrient requirements, supporting the need to give more consideration to special nutrient requirements in disease states.

Role of nurses in addressing modifiable risk factors for early Alzheimer's disease and mild cognitive impairment

A multidisciplinary advisory group of health professionals involved in dementia care assessed the current evidence base regarding modifiable risk factors (MRFs) for early Alzheimer's disease and mild cognitive impairment. Based on evidence from the published literature and clinical experience, MRFs in four areas were identified where there is evidence to support interventions that may help delay cognitive decline or reduce the risk of developing Alzheimer's disease: medical (eg cardiovascular risk factors), psychosocial (eg depression, anxiety, social isolation), lifestyle (eg lack of physical activity, smoking) and nutrition (eg poor diet, lack of micronutrients). Practical guidance on how health professionals, but in particular nurses, may actively seek to address these MRFs in clinical practice was also developed. Nurses are at the forefront of patient care and, as such, are ideally placed to offer advice to patients that may proactively help mitigate the risks of cognitive decline and the development of Alzheimer's disease.

The LipiDiDiet trial: what does it add to the current evidence for Fortasyn Connect in early Alzheimer's disease?

Nutritional factors can influence the risk of developing Alzheimer’s disease (AD) and its rate of progression, and there is, therefore, increasing interest in nutrition as a modifiable risk factor for the disease. Synaptic loss is an important feature of early AD, and the formation of new synapses is dependent on key nutritional elements that are known to be deficient in patients with AD. The daily medical food, Souvenaid, contains Fortasyn Connect, a multinutrient combination developed to specifically address these deficiencies, comprising docosahexaenoic acid, eicosapentaenoic acid, uridine monophosphate, choline, phospholipids, selenium, folic acid, and vitamins B12, B6, C, and E. Although yielding heterogeneous findings, clinical studies of Fortasyn Connect provide preliminary evidence of clinically relevant benefits on cognitive outcomes in prodromal and early AD. The LipiDiDiet trial investigated the effects of Fortasyn Connect on cognition and related measures in prodromal AD, and is the first randomized, controlled, double-blind, multicenter trial study of a non-pharmacological intervention in this setting. The primary efficacy endpoint was change over 24 months in a composite score of cognitive performance using a neuropsychological test battery. Fortasyn Connect had no significant effect on this endpoint, but demonstrated a significant benefit on secondary endpoints, including domains of cognition affected by AD (attention, memory, executive function) and hippocampal atrophy, suggesting a potential benefit on disease progression. Other studies have demonstrated benefits for Fortasyn Connect on nutritional markers and levels of plasma homocysteine. Taken together, current evidence indicates that Fortasyn Connect may show benefit on domains of cognition affected by AD and nutritional measures that influence risk factors for its progression; that it has greater potential for benefit earlier rather than later in the disease; and that it is safe and well tolerated, alone or in combination with AD medications. Further research into its potential role in AD management is therefore warranted.

A blend containing docosahexaenoic acid, arachidonic acid, vitamin B12, vitamin B9, iron and sphingomyelin promotes myelination in an in vitro model

During the development of the central nervous system, oligodendrocytes (OLs) are responsible for myelination, the formation of the myelin sheath around axons. This process enhances neuronal connectivity and supports the maturation of emerging cognitive functions. In humans, recent evidence suggests that early life nutrition may affect myelination. In the present study, we investigated the impact of a blend containing docosahexaenoic acid, arachidonic acid, vitamin B12, vitamin B9, iron and sphingomyelin, or each of these nutrients individually, on oligodendrocyte precursor cells (OPCs) proliferation and maturation into OLs as well as their myelinating properties. By using an in vitro model, developed to study each step of myelination, we found that the nutrient blend increased the number of OPCs and promoted their differentiation and maturation into OLs, as measured by quantifying A2B5 positive cells, myelin-associated glycoprotein (MAG) positive cells and area, myelin binding protein (MBP) positive cells and area, respectively. Moreover, measuring myelination by quantifying the overlapping signal between neurofilament and either MAG or MBP revealed a positive effect of the blend on OLs myelinating properties. In contrast, treatment with each individual nutrient resulted in differential effects on the various readouts. This work suggests that dietary intake of these nutrients during early life, might be beneficial for myelination.

An anthraquinone compound and its protective effects against homocysteine-induced cytotoxicity and oxidative stress

In this work, we designed an anthraquinone derivative: 1,4-diacrylateanthracene-9,10-dione (DAAD) with antioxidant activity for preventing Alzheimer's disease (AD) through preventing the neurotoxicity of Homocysteine (Hcy). This compound has very low cytotoxicity and protects the cells against Hcy-induced cytotoxicity and oxidative stress. Thus, maybe DAAD can be used as a potential reagent to preventing AD. In addition, we investigated the UV-Vis and fluorescence spectra of DAAD in PBS (pH 7.29)/DMSO (v/v, 1:1) solution for detecting Hcy, and the detection limit of DAAD for Hcy was found to be 0.121 μM. Thus, DAAD also can be used to monitor the Hcy level in plasma and cells.

[Endothelium as a target for new therapeutic strategies in cerebral vascular diseases]

The author evaluates a role of endothelium in the pathogenesis of cerebral vascular diseases (CVD) and considers the concept about endothelium as prevention and treatment of pathological processes leading to or triggering CVD. There are two medical strategies for correction of endothelium dysfunction in CVD: tactic (using of antioxidants) and strategic (statins, hypotensive drugs, antiaggregants).

Role of Homocysteine in Cognitive Impairement and Alzheimer's Disease

A high circulating concentration of the non proteinogenic amino acid homocysteine has been implicated as a risk factor for Alzheimer's Disease and its prodromal stage, mild cognitive impairement. Furthermore, hyperhomocysteinaemia has been directly attributed to a deficiency in vitamins B12, folate, and B6. Several studies have demonstrated decrease in progression of mild cognitive impairement to Alzheimer's Disease, and some have even shown an improvement in cognition after vitamin supplements with B12 and folate. Plausible mechanisms linking hyperhomocysteinaemia to Alzheimer's and cognitive impairement have been hypothesized and demonstrated in hyperhomocysteinemic mice models. However, some studies have not elucidated any benefit of vitamin supplements in subjects with cognitive impairment. Hence, multicentric clinical studies need to be conducted to substantiate the mechanisms of neuronal degeneration due to hyperhomocysteinaemia and to demonstrate the beneficial effect of folate, B6 and B12 supplements on cognition.

Lower brain and blood nutrient status in Alzheimer's disease: Results from meta-analyses

INTRODUCTION

Alzheimer's disease (AD) patients are at risk of nutritional insufficiencies because of physiological and psychological factors. Recently, we showed the results of the meta-analyses indicating lower plasma levels of vitamins A, B12, C, E, and folate in AD patients compared with cognitively intact elderly controls (controls). Now, additional and more extensive literature searches were performed selecting studies which compare blood and brain/cerebrospinal fluid (CSF) levels of vitamins, minerals, trace elements, micronutrients, and fatty acids in AD patients versus controls.

METHODS

The literature published after 1980 in Cochrane Central Register of Controlled Trials, Medline, and Embase electronic databases was systematically analyzed using Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines to detect studies meeting the selection criteria. Search terms used are as follows: AD patients, Controls, vitamins, minerals, trace elements, micronutrients, and fatty acids. Random-effects meta-analyses using a linear mixed model with correction for age differences between AD patients and controls were performed when four or more publications were retrieved for a specific nutrient.

RESULTS

Random-effects meta-analyses of 116 selected publications showed significant lower CSF/brain levels of docosahexaenoic acid (DHA), choline-containing lipids, folate, vitamin B12, vitamin C, and vitamin E. In addition, AD patients showed lower circulatory levels of DHA, eicosapentaenoic acid, choline as phosphatidylcholine, and selenium.

CONCLUSION

The current data show that patients with AD have lower CSF/brain availability of DHA, choline, vitamin B12, folate, vitamin C, and vitamin E. Directionally, brain nutrient status appears to parallel the lower circulatory nutrient status; however, more studies are required measuring simultaneously circulatory and central nutrient status to obtain better insight in this observation. The brain is dependent on nutrient supply from the circulation, which in combination with nutrient involvement in AD-pathophysiological mechanisms suggests that patients with AD may have specific nutritional requirements. This hypothesis could be tested using a multicomponent nutritional intervention.

Nutrients required for phospholipid synthesis are lower in blood and cerebrospinal fluid in mild cognitive impairment and Alzheimer's disease dementia

INTRODUCTION

Synaptic membrane formation depends on nutrients that fuel metabolic pathways for the synthesis of constituent phospholipids. Consequently, insufficient availability of such nutrients may restrict membrane formation and contribute to synaptic dysfunction in Alzheimer's disease (AD). We assessed whether blood and cerebrospinal fluid (CSF) concentrations of nutrients related to phospholipid synthesis differ among patients with AD, mild cognitive impairment (MCI), and control subjects.

METHODS

Concentrations of uridine, choline, folate, homocysteine, and other related metabolites were analyzed in paired blood and CSF samples from subjects selected from the Amsterdam Dementia Cohort with AD (n = 150; age, 66 ± 7 years; 37% female), MCI (n = 148; age, 66 ± 8 years; 37% female), and control subjects (n = 148; age, 59 ± 8 years; 38% female).

RESULTS

Age- and gender-adjusted analysis of variance revealed different concentrations of circulating uridine, choline, and folate and CSF uridine, folate, and homocysteine (all P < .05) among the three diagnostic groups. Post hoc pairwise comparison showed that subjects with AD had lower CSF uridine, plasma choline and higher CSF homocysteine concentrations, whereas subjects with MCI had lower plasma and CSF uridine, serum and CSF folate, and higher CSF homocysteine concentrations compared with control subjects (all P < .05), with differences ranging from -11 to +22%.

DISCUSSION

AD and MCI patients have lower levels of nutrients involved in phospholipid synthesis. The current observations warrant exploration of the application of nutritional strategies in the early stages of AD.

Role of Homocysteine in Cognitive Impairement and Alzheimer's Disease

A high circulating concentration of the non proteinogenic amino acid homocysteine has been implicated as a risk factor for Alzheimer's Disease and its prodromal stage, mild cognitive impairement. Furthermore, hyperhomocysteinaemia has been directly attributed to a deficiency in vitamins B12, folate, and B6. Several studies have demonstrated decrease in progression of mild cognitive impairement to Alzheimer's Disease, and some have even shown an improvement in cognition after vitamin supplements with B12 and folate. Plausible mechanisms linking hyperhomocysteinaemia to Alzheimer's and cognitive impairement have been hypothesized and demonstrated in hyperhomocysteinemic mice models. However, some studies have not elucidated any benefit of vitamin supplements in subjects with cognitive impairment. Hence, multicentric clinical studies need to be conducted to substantiate the mechanisms of neuronal degeneration due to hyperhomocysteinaemia and to demonstrate the beneficial effect of folate, B6 and B12 supplements on cognition.

Associations between Homocysteine, Folic Acid, Vitamin B12 and Alzheimer's Disease: Insights from Meta-Analyses

The associations between homocysteine (Hcy), folic acid, and vitamin B12 and Alzheimer's disease (AD) have gained much interest, while remaining controversial. We aim to perform meta-analyses to evaluate comprehensively: i) Hcy, folic acid, and vitamin B12 levels in AD patients in comparison with controls; and ii) the association between Hcy, folic acid, and vitamin B12 levels and risk of AD. A literature search was performed using Medline and Scopus databases. A total of 68 studies were identified and included in the meta-analyses. Stata 12.0 statistical software was used to perform the meta-analyses. First, AD patients may have higher level of Hcy, and lower levels of folate and vitamin B12 in plasma than controls. Further age-subgroup analysis showed no age effect for Hcy levels in plasma between AD patients and matched controls, while the differences in folate and vitamin B12 levels further enlarged with increased age. Second, data suggests that high Hcy and low folate levels may correlate with increased risk of AD occurrence. The comprehensive meta-analyses not only confirmed higher Hcy, lower folic acid, and vitamin B12 levels in AD patients than controls, but also implicated that high Hcy and low folic acid levels may be risk factors of AD. Further studies are encouraged to elucidate mechanisms linking these conditions.

Metazoan remaining genes for essential amino acid biosynthesis: sequence conservation and evolutionary analyses

Essential amino acids (EAA) consist of a group of nine amino acids that animals are unable to synthesize via de novo pathways. Recently, it has been found that most metazoans lack the same set of enzymes responsible for the de novo EAA biosynthesis. Here we investigate the sequence conservation and evolution of all the metazoan remaining genes for EAA pathways. Initially, the set of all 49 enzymes responsible for the EAA de novo biosynthesis in yeast was retrieved. These enzymes were used as BLAST queries to search for similar sequences in a database containing 10 complete metazoan genomes. Eight enzymes typically attributed to EAA pathways were found to be ubiquitous in metazoan genomes, suggesting a conserved functional role. In this study, we address the question of how these genes evolved after losing their pathway partners. To do this, we compared metazoan genes with their fungal and plant orthologs. Using phylogenetic analysis with maximum likelihood, we found that acetolactate synthase (ALS) and betaine-homocysteine S-methyltransferase (BHMT) diverged from the expected Tree of Life (ToL) relationships. High sequence conservation in the paraphyletic group Plant-Fungi was identified for these two genes using a newly developed Python algorithm. Selective pressure analysis of ALS and BHMT protein sequences showed higher non-synonymous mutation ratios in comparisons between metazoans/fungi and metazoans/plants, supporting the hypothesis that these two genes have undergone non-ToL evolution in animals.

Plasma homocysteine, Alzheimer and cerebrovascular pathology: a population-based autopsy study

Elevated plasma total homocysteine is associated with increased risk of dementia/Alzheimer's disease, but underlying pathophysiological mechanisms are not fully understood. This study investigated possible links between baseline homocysteine, and post-mortem neuropathological and magnetic resonance imaging findings up to 10 years later in the Vantaa 85+ population including people aged ≥85 years. Two hundred and sixty-five individuals had homocysteine and autopsy data, of which 103 had post-mortem brain magnetic resonance imaging scans. Methenamine silver staining was used for amyloid-β and modified Bielschowsky method for neurofibrillary tangles and neuritic plaques. Macroscopic infarcts were identified from cerebral hemispheres, brainstem and cerebellum slices. Standardized methods were used to determine microscopic infarcts, cerebral amyoloid angiopathy, and α-synuclein pathology. Magnetic resonance imaging was used for visual ratings of the degree of medial temporal lobe atrophy, and periventricular and deep white matter hyperintensities. Elevated baseline homocysteine was associated with increased neurofibrillary tangles count at the time of death: for the highest homocysteine quartile, odds ratio (95% confidence interval) was 2.60 (1.28-5.28). The association was observed particularly in people with dementia, in the presence of cerebral infarcts, and with longer time between the baseline homocysteine assessment and death. Also, elevated homocysteine tended to relate to amyloid-β accumulation, but this was seen only with longer baseline-death interval: odds ratio (95% confidence interval) was 2.52 (0.88-7.19) for the highest homocysteine quartile. On post-mortem magnetic resonance imaging, for the highest homocysteine quartile odds ratio (95% confidence interval) was 3.78 (1.12-12.79) for more severe medial temporal atrophy and 4.69 (1.14-19.33) for more severe periventricular white matter hyperintensities. All associations were independent of several potential confounders, including common vascular risk factors. No relationships between homocysteine and cerebral macro- or microinfarcts, cerebral amyoloid angiopathy or α-synuclein pathology were detected. These results suggest that elevated homocysteine in adults aged ≥85 years may contribute to increased Alzheimer-type pathology, particularly neurofibrillary tangles burden. This effect seems to be more pronounced in the presence of cerebrovascular pathology. Randomized controlled trials are needed to determine the impact of homocysteine-lowering treatments on dementia-related pathology.

Alterations in metabolic pathways and networks in Alzheimer's disease

The pathogenic mechanisms of Alzheimer's disease (AD) remain largely unknown and clinical trials have not demonstrated significant benefit. Biochemical characterization of AD and its prodromal phase may provide new diagnostic and therapeutic insights. We used targeted metabolomics platform to profile cerebrospinal fluid (CSF) from AD (n=40), mild cognitive impairment (MCI, n=36) and control (n=38) subjects; univariate and multivariate analyses to define between-group differences; and partial least square-discriminant analysis models to classify diagnostic groups using CSF metabolomic profiles. A partial correlation network was built to link metabolic markers, protein markers and disease severity. AD subjects had elevated methionine (MET), 5-hydroxyindoleacetic acid (5-HIAA), vanillylmandelic acid, xanthosine and glutathione versus controls. MCI subjects had elevated 5-HIAA, MET, hypoxanthine and other metabolites versus controls. Metabolite ratios revealed changes within tryptophan, MET and purine pathways. Initial pathway analyses identified steps in several pathways that appear altered in AD and MCI. A partial correlation network showed total tau most directly related to norepinephrine and purine pathways; amyloid-β (Ab42) was related directly to an unidentified metabolite and indirectly to 5-HIAA and MET. These findings indicate that MCI and AD are associated with an overlapping pattern of perturbations in tryptophan, tyrosine, MET and purine pathways, and suggest that profound biochemical alterations are linked to abnormal Ab42 and tau metabolism. Metabolomics provides powerful tools to map interlinked biochemical pathway perturbations and study AD as a disease of network failure.

[Homocysteine, vitamin B-12, folic acid and the cognitive decline in the elderly]

Hyperhomocysteinemia is a risk factor for neurological diseases, but the underlying pathophysiology has not been adequately explained. Mild hyperhomocysteinemia, which is sometimes associated with a low plasma level of vitamin B9, B12 and folic acid, is responsible in the toxicity in neural cell by activating NMDA receptor. Indeed, even if vitamin supplementation has clearly proven its efficiency on lowering plasma levels of homocysteine, recent studies do not show any positive effect of vitamin therapy on cognitive function. The hypothesis that this therapy is inefficient has been recently reinforced by two randomized trials on the effects of vitamin supplementation. Several hypotheses still need to be explored: Mechanisms of homocysteine toxicity and that of total uselessness of vitamin supplementation; the possible need to complete the actual data with further, more powerful studies in order to prove the role of homocysteine in the development of neurodegenerative diseases and a clinical effect of vitamin therapy.

OPTIMIZING DIAGNOSIS AND MANANGEMENT IN MILD-TO-MODERATE ALZHEIMER'S DISEASE

Alzheimer's disease (AD) is characterized by progressive declines in cognitive function and ability to carry out activities of daily living; and the emergence and worsening of behavioral/neuropsychiatric symptoms. While there is no cure for AD, non-pharmacologic interventions and medications that modulate neurotransmission can slow symptomatic progression. Medical foods may also be useful as adjuncts to pharmacologic agents in AD. Medium chain triglycerides aimed at improving cerebral metabolism significantly improve Alzheimer's Disease Assessment Scale-Cognitive scores when added to ongoing pharmacotherapy in patients with mild-to-moderate AD. Combination of interventions, such as non-pharmacologic treatments, pharmacotherapy, and medical foods, with complementary mechanisms of action may provide a rational approach that may result in maximum preservation of cognitive function in patients with AD.