Folate and homocysteine metabolism in neural plasticity and neurodegenerative disorders

Protective effect of aqueous extract of Nigella sativa on Oxidative Enzymes, Homocysteine, and Lipids in Methionine induced Hyperhomocysteinemic rats

Hyperhomocysteinemia has emerged as an independent risk factor for development of various diseases such as coronary, cerebrovascular and peripheral arterial occlusive diseases. Its association is found with atherosclerosis, cancer and some other aged-related illnesses including Alzheimer’s disease. The present study was designed to investigate the homocysteine lowering potential, effect on lipids and oxidative enzymes of standardized aqueous extract of Nigella sativa seeds (100 and 200 mg/kg body weight, p.o.) in hyperhomocysteinemia induced by L-methionine. Hyperhomocysteinemia was induced in wistar albino rats by methionine treatment (1 g/kg, p.o.) for 30 days. Folic acid (100 mg/kg, p.o.) given to rats as a standard drug treatment. Rats were fed with the aqueous extract of Nigella sativa (100 and 200 mg/kg, p.o.) for 30 days. The results of the present study after treatment with Nigella sativa aqueous extracts in two doses of 100 and 200 mg/kg body weight, showed lipid lowering, cardio- and neuro-protective potential of Nigella sativa. The results of test drug were compared with folic acid, a standard positive control. The present study results indicate that the aqueous extract of Nigella sativa seeds treatment protect the antioxidant defense against hyperhomocysteinemia, hyperlipidemia and oxidative stress in methionine-induced rat model.

Influences of Vitamin B12 Supplementation on Cognition and Homocysteine in Patients with Vitamin B12 Deficiency and Cognitive Impairment

Vitamin B12 deficiency is associated with cognitive impairment, hyperhomocysteinemia, and hippocampal atrophy. However, the recovery of cognition with vitamin B12 supplementation remains controversial. Of the 1716 patients who visited our outpatient clinic for dementia, 83 had vitamin B12 deficiency. Among these, 39 patients (mean age, 80.1 ± 8.2 years) had undergone Mini-Mental State Examination (MMSE) and laboratory tests for vitamin B12, homocysteine (Hcy), and folic acid levels. The hippocampal volume was estimated using the z-score of the MRI-voxel-based specific regional analysis system for Alzheimer’s disease. This is multi-center, open-label, single-arm study. All the 39 patients were administered vitamin B12 and underwent reassessment to measure the retested for MMSE and Hcy after 21−133 days (median = 56 days, interquartile range (IQR) = 43−79 days). After vitamin B12 supplementation, the mean MMSE score improved significantly from 20.5 ± 6.4 to 22.9 ± 5.5 (p < 0.001). Hcy level decreased significantly from 22.9 ± 16.9 nmol/mL to 11.5 ± 3.9 nmol/mL (p < 0.001). Significant correlation was detected between the extent of change in MMSE scores and baseline Hcy values. The degree of MMSE score was not correlated with hippocampal atrophy assessed by the z-score. While several other factors should be considered, vitamin B12 supplementation resulted in improved cognitive function, at least in the short term, in patients with vitamin B12 deficiency.

Elevation of Plasma Homocysteine and Minor Hallucinations in Parkinson’s Disease: A Cross-Sectional Study

Purpose

Minor hallucinations (MHs) are the most common psychotic phenomena in Parkinson's disease (PD), and it has important clinical and prognostic implications in PD. Plasma homocysteine (Hcy) has been reported to predict the outcome of PD; whether or not Hcy is associated with MH is not known. We aim to investigate the Hcy level and related factors in patients with PD and MH.

Methods

We conducted a cross-sectional study and included 99 patients with PD, 34 with MH, and 65 without any hallucinations. The clinical and demographic data of the patients with and without hallucinations were compared. Hcy-related clinical factors were also analyzed.

Results

The plasma Hcy level was higher in MH patients than in patients without hallucinations, and the result was more pronounced in male patients than in female patients. Differences were also observed when the groups were divided on the basis of levodopa equivalent daily dose and disease duration. The high Hcy concentration was correlated with some symptoms in patients with MH, including motor dysfunction and nonmotor symptoms, such as symptoms of the gastrointestinal tract, angiocarpy, sleep/fatigue, and poor visuospatial/executive function.

Conclusions

Results indicated a higher plasma Hcy concentration in MH patients than in their counterparts and revealed that Hcy is associated with certain motor and nonmotor symptoms in patients with MH. Hcy may be a marker of MH and have important therapeutic implications in PD.

The impact of uremic toxins on Alzheimer's disease

Alzheimer's disease (AD) is the most common type of dementia, pathologically characterized by accumulation of senile plaques and neurofibrillary tangles. Chronic kidney disease (CKD) is highly prevalent in elderly population closely associated with occurrence of dementia. Recent epidemiological and experimental studies suggest a potential association of CKD with AD. Both diseases share a panel of identical risk factors, such as type 2 diabetes; and hypertension. However, the relationship between CKD and AD is unclear. Lower clearance of a panel of uremic toxin including cystatin-C, guanidine, and adiponectin due to CKD is implied to contribute to AD pathogenesis. In this review we summarize the current evidence from epidemiological, experimental and clinical studies on the potential contribution of uremic toxins to AD pathogenesis. We describe outstanding questions and propose an outlook on the link between uremic toxins and AD.

Serum Vitamins and Homocysteine Levels in Obsessive-Compulsive Disorder: A Systematic Review and Meta-Analysis

Vitamin and homocysteine (Hcy) alternations have been associated with psychiatric disorders. The aim of this meta-analysis was to assess the association of serum vitamin and Hcy levels with obsessive-compulsive disorder (OCD). Following PRISMA protocol, we used the databases including Scopus, PubMed, Google Scholar, and Web of Science with no time restriction. Data were pooled using a random-effects model and/or fixed-effects model to estimate the standard mean difference (SMD) for evaluation of the strength of association analyses. Our data showed a significant reduction in vitamin B12 (SMD = -0.58, 95% CI = -1.08 to -0.08, p = 0.02, I2 = 65%; pheterogeneity = 0.06), vitamin E (SMD = -0.89, 95% CI = -1.23 to -0.56, p < 0.00001, I2 = 23%; pheterogeneity = 0.26), and vitamin C (SMD = -1.40, 95% CI = -2.44 to -0.36, p = 0.008, I2 = 92%; pheterogeneity < 0.0001) in OCD patients. In addition, the findings showed significantly higher levels of Hcy (SMD = 1.11, 95% CI = [0.48, 1.75], p = 0.0006, I2 = 73%; ph = 0.02) in patients compared to controls. Also, our data showed that vitamin B9 and D levels are not associated with OCD (vitamin B9: SMD = -0.23, 95% CI = -1.01 to 0.55, p = 0.56, I2 = 88%; pheterogeneity < 0.0001; vitamin D: SMD = -0.63, 95% CI = -1.41 to 0.15, p = 0.11, I2 = 88%; pheterogeneity = 0.0002). Our findings support significant impacts of Hcy and vitamin B12, E, and C levels in OCD pathogenesis. This will be important for prevention and treatment of OCD. However, further studies are recommended to elucidate more accurate conclusions.

Vegetable and Fruit Intake, Its Patterns, and Cognitive Function: Cross-Sectional Findings among Older Adults in Anhui, China

OBJECTIVES

To examine the associations of vegetable and fruit intake frequency, its patterns, and cognition among older Chinese adults.

DESIGN

Cross-sectional data obtained from the Anhui Province Healthy Longevity Survey.

SETTING

Urban and rural communities.

PARTICIPANTS

A total of 5410 older adults (aged 60 or older) were included from selected communities.

MEASUREMENTS

Data on the number of days in a typical week that vegetables and fruits were consumed were collected, and the four intake patterns were defined (V+/F+: daily intake of both vegetables and fruit; V+/F- or V-/F+: daily intake of vegetables or fruit; and V-/F-: no daily intake of either vegetables or fruit). Cognitive function was measured using the Mini-mental State Examination (MMSE), and mild cognitive impairment (MCI) was defined according to education-specific criteria.

RESULTS

Nondaily vegetable intake was associated with lower MMSE scores (β = -0.763, 95% confidence interval (CI): -1.463, -0.064) among males and a higher likelihood of having MCI (OR: 1.409, 95% CI: 1.037, 1.915) among females. Less frequent intake of fruit was associated with lower MMSE scores and a higher prevalence of MCI among both males and females (p for trends < 0.001 for both sexes). Compared with the V+/F+ group, male participants who were classified into the V+/F- and V-/F- groups had lower MMSE scores (V+/F-: β = -0.612, 95% CI: -1.094, -0.131; V-/F-: β = -1.273, 95% CI: -2.090, -0.455). Females classified in the V+/F- and V-/F- patterns had lower MMSE scores (V+/F-: β = -0.862, 95% CI: -1.320, -0.404; V-/F-: β = -1.293, 95% CI: -2.079, -0.507) and elevated risks of MCI (V+/F-: OR: 1.762, 95% CI: 1.386, 2.242; V-/F-: OR: 2.180, 95% CI: 1.505, 3.156).

CONCLUSION

Lower vegetable or fruit intake was associated with poorer cognitive performance among males and females, and the risk was even higher among those with a low intake of both vegetables and fruits. Healthy eating habits, including daily vegetable and fruit intake, are essential for cognition maintenance in both males and females.

Oxidative Stress in Autism Spectrum Disorder-Current Progress of Mechanisms and Biomarkers

Autism spectrum disorder (ASD) is a type of neurodevelopmental disorder that has been diagnosed in an increasing number of children around the world. Existing data suggest that early diagnosis and intervention can improve ASD outcomes. However, the causes of ASD remain complex and unclear, and there are currently no clinical biomarkers for autism spectrum disorder. More mechanisms and biomarkers of autism have been found with the development of advanced technology such as mass spectrometry. Many recent studies have found a link between ASD and elevated oxidative stress, which may play a role in its development. ASD is caused by oxidative stress in several ways, including protein post-translational changes (e.g., carbonylation), abnormal metabolism (e.g., lipid peroxidation), and toxic buildup [e.g., reactive oxygen species (ROS)]. To detect elevated oxidative stress in ASD, various biomarkers have been developed and employed. This article summarizes recent studies about the mechanisms and biomarkers of oxidative stress. Potential biomarkers identified in this study could be used for early diagnosis and evaluation of ASD intervention, as well as to inform and target ASD pharmacological or nutritional treatment interventions.

Targeting DNA Methylation in the Adult Brain through Diet

Metabolism and nutrition have a significant role in epigenetic modifications such as DNA methylation, which can influence gene expression. Recently, it has been suggested that bioactive nutrients and gut microbiota can alter DNA methylation in the central nervous system (CNS) through the gut-brain axis, playing a crucial role in modulating CNS functions and, finally, behavior. Here, we will focus on the effect of metabolic signals in shaping brain DNA methylation during adulthood. We will provide an overview of potential interactions among diet, gastrointestinal microbiome and epigenetic alterations on brain methylation and behavior. In addition, the impact of different diet challenges on cytosine methylation dynamics in the adult brain will be discussed. Finally, we will explore new ways to modulate DNA hydroxymethylation, which is particularly abundant in neural tissue, through diet.

Amino Acid Profile in Malnourished Patients with Liver Cirrhosis and Its Modification with Oral Nutritional Supplements: Implications on Minimal Hepatic Encephalopathy

Low plasma levels of branched chain amino acids (BCAA) in liver cirrhosis are associated with hepatic encephalopathy (HE). We aimed to identify a metabolic signature of minimal hepatic encephalopathy (MHE) in malnourished cirrhotic patients and evaluate its modification with oral nutritional supplements (ONS) enriched with ß-Hydroxy-ß-methylbutyrate (HMB), a derivative of the BCAA leucine. Post hoc analysis was conducted on a double-blind placebo-controlled trial of 43 individuals with cirrhosis and malnutrition, who were randomized to receive, for 12 weeks, oral supplementation twice a day with either 220 mL of Ensure^® Plus Advance (HMB group, n = 22) or with 220 mL of Ensure^® Plus High Protein (HP group, n = 21). MHE evaluation was by psychometric hepatic encephalopathy score (PHES). Compared to the HP group, an HMB-specific treatment effect led to a larger increase in Val, Leu, Phe, Trp and BCAA fasting plasma levels. Both treatments increased Fischer’s ratio and urea without an increase in Gln or ammonia fasting plasma levels. MHE was associated with a reduced total plasma amino acid concentration, a reduced BCAA and Fischer´s ratio, and an increased Gln/Glu ratio. HMB-enriched ONS increased Fischer´s ratio without varying Gln or ammonia plasma levels in liver cirrhosis and malnutrition, a protective amino acid profile that can help prevent MHE.

Improvement of cognitive performance by a nutraceutical formulation: Underlying mechanisms revealed by laboratory studies

Cognitive decline, decrease in neuronal function and neuronal loss that accompany normal aging and dementia are the result of multiple mechanisms, many of which involve oxidative stress. Herein, we review these various mechanisms and identify pharmacological and non-pharmacological approaches, including modification of diet, that may reduce the risk and progression of cognitive decline. The optimal degree of neuronal protection is derived by combinations of, rather than individual, compounds. Compounds that provide antioxidant protection are particularly effective at delaying or improving cognitive performance in the early stages of Mild Cognitive Impairment and Alzheimer's disease. Laboratory studies confirm alleviation of oxidative damage in brain tissue. Lifestyle modifications show a degree of efficacy and may augment pharmacological approaches. Unfortunately, oxidative damage and resultant accumulation of biomarkers of neuronal damage can precede cognitive decline by years to decades. This underscores the importance of optimization of dietary enrichment, antioxidant supplementation and other lifestyle modifications during aging even for individuals who are cognitively intact.

An update on the treatment of premature ejaculation: A systematic review

To analyse the current therapeutic options for patients with premature ejaculation (PE) and highlight their mechanism(s) of action, effectiveness, advantages and limitations. A literature search was conducted using the PubMed database searching for articles exploring different PE treatment modalities. A Preferred Reporting Items for Systemic Reviews and Meta-Analyses (PRISMA) approach was used to report the results of the literature search. A total of 149 articles were included in this review. The currently available treatment methods for PE include behavioural therapy, local anaesthetics, tricyclic antidepressants, selective serotonin reuptake inhibitors, and selective phosphodiesterase inhibitors. Most PE treatments are either experimental or used off-label. New treatments are certainly warranted to overcome this exasperating sexual dysfunction.

Abbreviations: AIPE: Arabic Index of Premature Ejaculation; CNS: central nervous system; CYP: cytochrome P450; ED: erectile dysfunction; FDA: United States Food and Drug Administration; H1: histamine receptors; 5-HT: 5-hydroxytryptamine; IELT: The intravaginal ejaculation latency time; IPE: Index of Premature Ejaculation; M1: muscarinic receptors; OCD: obsessive–compulsive disorder; PDE5: phosphodiesterase type 5; PE: premature ejaculation; PEP: Premature Ejaculation Profile; PRO: patient-reported outcome; RCT: randomised controlled trial; SS: Severance Secret (cream); SSRIs: selective serotonin reuptake inhibitors; TCAs: tricyclic antidepressants

Quercetin fail to protect against the neurotoxic effects of chronic homocysteine administration on motor behavior and oxidative stress in the adult rat's cerebellum

Homocysteine (Hcy) is an excitatory amino acid that contains thiol group and derives from the methionine metabolism. It increases vulnerability of the neuronal cells to excitotoxic and oxidative damage. This study aimed to investigate the hyperhomocysteinemia (hHcy) effects on rat cerebellum and the possible protective role of quercetin administration in Hcy-treated rats, using behavioral and biochemical analyzes. To this end, the adult male rats were divided randomly into the control group that received vehicle, Hcy group received Hcy (400 μg/kg), Hcy + Que group received Hcy + quercetin (50 mg/kg), quercetin group received quercetin for 14 days. On Day 14 after the final treatment, lipid peroxidation level, the superoxide dismutase (SOD), and glutathione peroxidase (GPx) activities were evaluated in the cerebellum. After completion of treatment, the rat's performance on rotarod and locomotor activity was evaluated. The results showed that Hcy treatment elicited cerebellar lipid peroxidation, impaired locomotor activity and increased latency to fall on the rotarod. Quercetin failed to attenuate significantly motoric impairment, increased significantly the cerebellar lipid peroxidation and GPx activity in the Hcy + Que group. Our results suggest that Hcy induced cerebellar toxicity and quercetin had no significant protective effects against Hcy toxicity in the cerebellum of adult rats.

Early Life Nutrition and Mental Health: The Role of DNA Methylation

Does the quality of our diet during early life impact our long-term mental health? Accumulating evidence suggests that nutrition interacts with our genes and that there is a strong association between the quality of diet and mental health throughout life. Environmental influences such as maternal diet during pregnancy or offspring diet have been shown to cause epigenetic changes during critical periods of development, such as chemical modifications of DNA or histones by methylation for the regulation of gene expression. One-carbon metabolism, which consists of the folate and methionine cycles, is influenced by the diet and generates S-Adenosylmethinoine (SAM), the main methyl donor for methylation reactions such as DNA and histone methylation. This review provides current knowledge on how the levels of one-carbon metabolism associated micronutrients such as choline, betaine, folate, methionine and B vitamins that play a role in brain function can impact our well-being and mental health across the lifespan. Micronutrients that act as methyl donors for SAM formation could affect global or gene methylation, altering gene expression and phenotype. Strategies should then be adopted to better understand how these nutrients work and their impact at different stages of development to provide individualized dietary recommendations for better mental health outcomes.

Effects of Supplementation with Folic Acid and Its Combinations with Other Nutrients on Cognitive Impairment and Alzheimer's Disease: A Narrative Review

Cognitive impairment and Alzheimer's Disease, among other cognitive dysfunctions, has been recognized as a major public health problem. Folic acid is a well-known essential nutrient whose deficiency has been linked to neurocognitive dysfunctions, owing to hyperhomocysteinemia, an independent risk factor for cardio- and cerebrovascular diseases, including cognitive impairment, Alzheimer's Disease, and vascular dementia. However, to date, there is certain controversy about the efficacy of vitamin supplementation in patients with these pathologies. Therefore, we have reviewed the available dietary intervention studies based on folic acid, either alone or in combination with different vitamins or nutrients into the progression of Alzheimer's Disease and Cognitive impairment, highlighting the cognition and biochemical markers employed for the evaluation of the disease progression. Undeniably, the compiled information supports the potential benefits of vitamin supplementation in these pathologies, especially relevant to the aging process and quality of life, although more research is urgently needed to confirm these positive findings.

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

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

Functional inhibition of redox regulated heme proteins: A novel mechanism towards oxidative stress induced by homocysteine

Homocysteine (Hcy) is a sulfur containing non-protein toxic amino acid synthesized from methionine. Elevated level of Hcy is associated with cardiovascular complications and neurodegeneration. Hcy is believed to induce organ damage and apoptosis via oxidative stress. The pro-oxidant nature of Hcy is considered to originate from the metal-induced oxidation of thiol group-containing molecules forming disulfides (Hcy-Hcy, Hcy-cysteine, Hcy-glutathione, etc) or with free cysteine residues of proteins (a process called protein S-homocysteinylation). Formation of such disulfides indeed results in the generation of reactive oxygen species (ROS) which eventually leads to loss of cellular integrity. In the present manuscript, we performed systematic investigation of the effect of Hcy on iron containing proteins. We discover a novel mechanism of Hcy toxicity wherein Hcy oxidation is linked with the functional loss of the protein with iron as cofactors. Our results indicate that redox regulated heme proteins might be primarily involved in the Hcy toxicity and associated oxidative stress.

Homocysteine restrains hippocampal neurogenesis in focal ischemic rat brain by inhibiting DNA methylation

Ischemic stroke represents a major cause of mortality worldwide. An elevated level of homocysteine (Hcy) is recognized as a powerful risk factor of ischemic stroke. We previously reported that Hcy induces cytotoxicity and proliferation inhibition in neural stem cells (NSCs) derived from the neonatal rat hippocampus in vitro. However, the toxic potential of Hcy on NSCs and its underlying mechanisms are not entirely clear in ischemic brain. Since DNA methylation is critical for establishing the diverse cell fates in the central nervous system, we hypothesized that negative effect of Hcy (an intermediate in the one-carbon metabolism) on neurogenesis might be link to DNA methylation in ischemic stroke. In our study, the rats in Hcy intervention group were intraperitoneally injected with 2% Hcy solution (5 mL/kg/d) for 7 consecutive days before MCAO surgery until they were sacrificed. Our study indicated that Hcy inhibited NSCs self-renewal capacity, which was exhibited by lowering the number of DCX+/BrdU+ and NeuN+/BrdU+ in ischemic brain hippocampus. A reduction in the activity of the DNA methyltransferases (DNMTs), total methylation level and the number of 5mC+/NeuN+ and DCX+/5mC+ cells was observed in Hcy-treated ischemic brains. Additionally, Hcy also induced an increase in S-adenosylhomocysteine (SAH), and a decrease in the ratio of S-adenosylmethionine (SAM) to SAH. These results suggest that the alterations in DNA methylation may be an important mechanism by which Hcy inhibits neurogenesis after stroke. Hcy-induced DNA hypomethylation may be mainly caused by a reduction in the DNMT activity which is regulated by the concentrations of SAM and SAH. Maintaining normal DNA methylation by lowering Hcy level may possess therapeutic potential for promoting neurological recovery and reconstruction after stroke.

Serum Folic Acid and Erectile Dysfunction: A Systematic Review and Meta-Analysis

Introduction

The association between folic acid (FA) and erectile dysfunction (ED) was contradictory in the published original articles, and no meta-analysis was conducted to pool these data.

Aim

To verify the role of FA in the pathology of ED and explore the treatment efficacy of FA for ED patients.

Methods

An extensive search was performed on PubMed, Cochrane Library, and Web of Science to obtain all relevant studies published up to October 31, 2020. Studies comparing the serum FA level between ED patients and healthy controls, or comparing the score of the IIEF-5, or IIEF before and after folic acid therapy alone or combination in ED patient were eligible for our meta-analysis. The Newcastle-Ottawa Scales (NOS) was used to qualify included studies.

Main Outcome Measures

The standardized mean differences (SMD) and their corresponding 95% confidence intervals (95% CIs) were calculated to pool our data.

Results

Nine studies were eligible for our meta-analysis to verify the association between FA and ED, and to explore the treatment efficacy of FA for ED patients. The pooled SMD of the FA level difference between ED patients and healthy subjects was -0.94 (95% CI: -1.59, -0.30, P = .004). Moreover, the level of folic acid in healthy subjects, Mild ED patients, Moderate ED patients and Severe ED patients was 11.847 (95%CI = 9.671, 14.022), 9.496 (95%CI = 8.425, 10.567), 6.597 (95%CI = 5.187, 8.007) and 5.623 (95%CI = 3.535, 7.711) respectively. The SMD of changes in score of IIEF-5 was 1.89 with 95%CI (1.60, 2.17) after FA administration in ED patients. Our analysis also showed that combination therapy of FA plus tadalafil changed the score of IIEF with 0.90 (95%CI = 0.44, 1.36) comparing to combination of placebo plus tadalafil.

Conclusion

This novel meta-analysis demonstrated that FA was an independent risk factor for ED and FA supplement may have potentially positive effects in the treatment of ED patients.

Zhang Y, Zhang W, Dai Y, et al. Serum Folic Acid and Erectile Dysfunction: A Systematic Review and Meta-Analysis. Sex Med 2021;9:100356.

Folate metabolizing gene polymorphisms and genetic vulnerability to preterm birth in Korean women

BACKGROUND

The folate metabolism that converts homocysteine to methionine is closely related to the accumulation of homocysteine. Increased homocysteine levels lead to an impaired antithrombotic function of the vascular endothelium and uterine-placental circulation, resulting in abnormal pregnancy outcomes. Previous studies have reported that gene polymorphisms in folate metabolism are associated with the development of preterm birth (PTB) in various populations.

OBJECTIVE

we performed a case-control study to evaluate the association between five polymorphisms in folate metabolic genes (MTHFR, MTR, MTRR, TCN2) and PTB.

METHODS

In this study, a total of 254 subjects were analyzed (111 patients with PTB and 143 women at ≥ 38 weeks of gestation). Genotype and allele frequency differences between patients and control groups and the Hardy-Weinberg equilibrium were assessed using a Chi-square test. For evaluation indicators, odds ratios (ORs) of 95% confidence intervals (CI) were estimated. In addition, we analyzed the combined genotype frequencies of SNPs of folate-metabolizing genes to measure gene-gene interactions for PTB.

RESULTS

Our results showed that the MTR rs1805087 GG (p = 0.031), and TCN2 rs1801198 CG genotype (OR 0.53, 95% CI 0.288-0.980, p = 0.042) were significantly associated with PTB. The MTHFR rs4846049 AA showed a marginal trend toward significance (OR 0.15, 95% CI 0.018-1.205, p = 0.041). In particular, the combined genotypes, including MTHFR rs1537514 CC-MTRR rs1801394 GG, MTHFR rs1537514 CC-TCN2 rs1801198 CG, and MTR rs1805087 AA-TCN2 rs1801198 CG, have significant interactions with PTB (OR 0.49, 95% CI 0.248-0.992, p < 0.05).

CONCLUSION

The polymorphisms of folate metabolic genes may have a genetic association with the development of PTB in Korean women. A larger sample set and functional studies are required to further elucidate our findings.

Adenosine Inhibits Cell Proliferation Differently in Human Astrocytes and in Glioblastoma Cell Lines

Glioblastoma (GBM) is the most common brain primary tumour. Hypoxic regions in GBM are associated to tumour growth. Adenosine accumulates in hypoxic regions and can affect cell proliferation and survival. However, how proliferating GBM cells respond/adapt to increased adenosine levels compared to human astrocytes (HA) is not clarified and was addressed in the present work. GBM cell lines and HA were treated for 3 days with test drugs. Thirty Adenosine (30 µM) caused a 43% ± 5% (P < 0.05) reduction of cell proliferation/viability in HA, through an adenosine receptor-independent mechanism, but had no effect in GBM cell lines U87MG, U373MG and SNB19. Contrastingly, inhibition of adenosine phosphorylation (using the adenosine kinase (ADK) inhibitor 5-iodotubercidin (ITU) (25 µM)), produced a strong and similar decrease on cell proliferation in both HA and GBM cells. The effect of adenosine on HA proliferation/viability was potentiated by 100 µM-homocysteine. Combined application of 30 µM-adenosine and 100 µM-homocysteine reduced the cell proliferation/viability in all three GBM cell lines, but this reduction was much lower than that observed in HA. Adenosine alone did not induce cell death, assessed by lactate dehydrogenase (LDH) release, both in HA and GBM cells, but potentiated the cytotoxic effect of homocysteine in HA and in U87MG and U373MG cells. Results show a strong attenuation of adenosine anti-proliferative effect in GBM cells compared to HA, probably resulting from increased adenosine elimination by ADK, suggesting a proliferative-prone adaptation of tumour cells to increased adenosine levels.

Cerebral blood flow alterations in hemodialysis patients with and without restless legs syndrome: an arterial spin labeling study

Hemodialysis with restless legs syndrome (HD-RLS) is associated with alterations in neuronal function, the blood-brain barrier and iron deposition, thus affecting cerebral metabolism and perfusion. This study utilized three-dimensional arterial spin labeling (ASL) to identify HD-RLS-related perfusion patterns and potential relationships with disease severity. Twenty-six HD-RLS patients, 30 hemodialysis patients without restless legs syndrome (HD-nRLS) and 30 age-, sex-, and education-matched healthy controls were included in this study. One-way analysis of covariance and post hoc analyses were used to assess differences in cerebral blood flow (CBF) values, demographics and clinical data among the three groups. Pearson's correlation analysis was conducted between altered CBF values in the HD-RLS group and clinical data. Compared with HD-nRLS patients, HD-RLS patients showed increased CBF in the right primary motor cortex (false discovery rate [FDR]-corrected P < 0.05). Compared with the normal controls, both HD subgroups (i.e., those with and without RLS) exhibited consistent CBF changes, including increased CBF in the left medial superior frontal gyrus and bilateral thalamus and decreased CBF in the left insular cortices (FDR-corrected P < 0.05). This abnormal hyperperfusion in the sensorimotor cortex and basal ganglia provides evidence for a sensory processing disorder in RLS that may be involved in the pathogenesis of RLS in HD patients.

The Effects of Bariatric Surgery on Vitamin B Status and Mental Health

Diet is a modifiable factor that ensures optimal growth, biochemical performance, improved mood and mental functioning. Lack of nutrients, notably vitamin B, has an impact on human health and wellbeing. The United Arab Emirates is facing a serious problem of micronutrient deficiencies because of the growing trend for bariatric surgery, including Roux-en-Y gastric bypass and sleeve gastrectomy. People undergoing bariatric surgery are at high risk of developing neurological, cognitive, and mental disabilities and cardiovascular disease due to deficiency in vitamin B. Vitamin B is involved in neurotransmitter synthesis, including γ-aminobutyric acid, serotonin, dopamine, and noradrenaline. Deficiency of vitamin B increases the risk of depression, anxiety, dementia and Alzheimer's disease. In addition, vitamin B deficiency can disrupt the methylation of homocysteine, leading to hyperhomocysteinemia. Elevated homocysteine levels are detrimental to human health. Vitamin B deficiency also suppresses immune function, increases the production of pro-inflammatory cytokines and upregulates NF-κB. Considering the important functions of vitamin B and the severe consequences associated with its deficiency following bariatric surgery, proper dietary intervention and administration of adequate supplements should be considered to prevent negative clinical outcomes.

A Mendelian Randomization Study of Plasma Homocysteine Levels and Cerebrovascular and Neurodegenerative Diseases

Background: Homocysteine (Hcy) is a toxic amino acid and hyperhomocysteinemia (HHcy) was reported to be associated with both cerebrovascular disease and neurodegenerative disease. Our aim was to assess the causal link between plasma Hcy level and cerebrovascular and neurodegenerative diseases through a Mendelian randomization (MR) study.

Methods: A two-sample MR study was performed to infer the causal link. We extracted the genetic variants (SNPs) associated with plasma Hcy level from a large genome-wide association study (GWAS) meta-analysis. The main MR analysis was performed using the inverse variance-weighted method. Additional analyses were further performed using MR-Egger intercept and Cochran’s Q statistic to detect the heterogeneity or pleiotropy of our findings.

Results: Thirteen Hcy-associated SNPs were selected as instrumental variables. The results showed evidence of a causal link between plasma Hcy level and ischemic stroke (IS) caused by small artery occlusion (SAS, OR = 1.329, 95% CI 1.047–1.612, p = 0.048). Meanwhile, there was no evidence of association between plasma Hcy level and other types of IS, transient ischemic attack (TIA), or neurodegenerative disease. The MR-Egger intercept test indicated no evidence of directional pleiotropy. Results of additional MR analysis indicated that blood pressure (BP) and type 2 diabetes mellitus (T2DM) serve as influencers in the association.

Conclusion: The MR study found a little causal link between plasma Hcy level and SAS. The link is likely to be influenced by other risk factors like BP and T2DM.

Neurology of inflammatory bowel disease

Inflammatory bowel diseases (IBD) are chronic inflammatory conditions affecting the digestive system, comprising two main distinctive entities, ulcerative colitis (UC) and Crohn's disease (CD). Besides gastrointestinal manifestations, IBD causes extraintestinal manifestations in the central and peripheral nervous system. The incidence of neurological complications in IBD ranges from 0.25% to 47.5%. The pathophysiology of neurological manifestations of IBD is mostly immune mediated, but dysfunction of the brain-gut axis, arterial and venous thromboembolism, infections, nutritional deficiencies and side-effects of medications (steroids, metronidazole, sulfasalazine, anti-TNF-α, anti-integrin antibodies) are other contributory mechanisms. Patients with IBD have an increased risk of arterial and venous stroke, mainly during periods of exacerbations. Vasculitis is extremely rare. There is a bidirectional association between multiple sclerosis and IBD, with a relative risk for comorbidity of 1.54, being 1.53 for the risk of multiple sclerosis in IBD and 1.55 for the risk of IBD in multiple sclerosis patients. Anti-TNF-α therapy is contraindicated in the treatment of patients who have both IBD and multiple sclerosis. Demyelinating disorders can also be a rare complication of anti-TNF-α therapy. Optic neuritis, transverse myelitis, progressive myelopathy, central nervous system infections, epilepsy and encephalopathy are among other uncommon neurological complications. Peripheral nervous system manifestations include peripheral neuropathy, either demyelination and axonal, myasthenia gravis and polymyositis/dermatomyositis and localized forms of myositis.

Nutraceuticals in the Prevention of Neonatal Hypoxia-Ischemia: A Comprehensive Review of their Neuroprotective Properties, Mechanisms of Action and Future Directions

Neonatal hypoxia-ischemia (HI) is a brain injury caused by oxygen deprivation to the brain due to birth asphyxia or reduced cerebral blood perfusion, and it often leads to lifelong limiting sequelae such as cerebral palsy, seizures, or mental retardation. HI remains one of the leading causes of neonatal mortality and morbidity worldwide, and current therapies are limited. Hypothermia has been successful in reducing mortality and some disabilities, but it is only applied to a subset of newborns that meet strict inclusion criteria. Given the unpredictable nature of the obstetric complications that contribute to neonatal HI, prophylactic treatments that prevent, rather than rescue, HI brain injury are emerging as a therapeutic alternative. Nutraceuticals are natural compounds present in the diet or used as dietary supplements that have antioxidant, anti-inflammatory, or antiapoptotic properties. This review summarizes the preclinical in vivo studies, mostly conducted on rodent models, that have investigated the neuroprotective properties of nutraceuticals in preventing and reducing HI-induced brain damage and cognitive impairments. The natural products reviewed include polyphenols, omega-3 fatty acids, vitamins, plant-derived compounds (tanshinones, sulforaphane, and capsaicin), and endogenous compounds (melatonin, carnitine, creatine, and lactate). These nutraceuticals were administered before the damage occurred, either to the mothers as a dietary supplement during pregnancy and/or lactation or to the pups prior to HI induction. To date, very few of these nutritional interventions have been investigated in humans, but we refer to those that have been successful in reducing ischemic stroke in adults. Overall, there is a robust body of preclinical evidence that supports the neuroprotective properties of nutraceuticals, and these may represent a safe and inexpensive nutritional strategy for the prevention of neonatal HI encephalopathy.

Elucidating the influence of environmentally relevant toxic metal mixture on molecular mechanisms involved in the development of neurodegenerative diseases: In silico toxicogenomic data-mining

This in silico toxicogenomic analysis aims to: (i) testify the hypothesis about the influence of the environmentally relevant toxic metals (lead, methylmercury (organic form of mercury), cadmium and arsenic) on molecular mechanisms involved in amyotrophic lateral sclerosis (ALS), Parkinson's Disease (PD) and Alzheimer's disease (AD) development; and (ii) demonstrate the capability of in silico toxicogenomic data-mining for distinguishing the probable mechanisms of mixture-induced toxic effects. The Comparative Toxicogenomics Database (CTD; http://ctd. mdibl.org) and Cytoscape software were used as the main data-mining tools in this analysis. The results have shown that there were 7, 13 and 14 common genes for all the metals present in the mixture for each of the selected neurodegenerative disease (ND), respectively: ALS, PD and AD. Physical interactions (68.18%) were the most prominent interactions between the genes extracted for ALS, co-expression (60.85%) for PD and interactions predicted by the server (44.30%) for AD. SOD2 gene was noted as the mutual gene for all the selected ND. Oxidative stress, folate metabolism, vitamin B12, AGE-RAGE, apoptosis were noted as the key disrupted molecular pathways that contribute to the neurodegenerative disease's development. Gene ontology analysis revealed biological processes affected by the investigated mixture (glutathione metabolic process was listed as the most important for ALS, cellular response to toxic substance for PD, and neuron death for AD). Our results emphasize the role of oxidative stress, particularly SOD2, in neurodegeneration triggered by environmental toxic metal mixture and give a new insight into common molecular mechanisms involved in ALS, PD and AD pathology.

Epigenetics of the developing and aging brain: Mechanisms that regulate onset and outcomes of brain reorganization

Brain development is a life-long process that encompasses several critical periods of transition, during which significant cognitive changes occur. Embryonic development, puberty, and reproductive senescence are all periods of transition that are hypersensitive to environmental factors. Rather than isolated episodes, each transition builds upon the last and is influenced by consequential changes that occur in the transition before it. Epigenetic marks, such as DNA methylation and histone modifications, provide mechanisms by which early events can influence development, cognition, and health outcomes. For example, parental environment influences imprinting patterns in gamete cells, which ultimately impacts gene expression in the embryo which may result in hypersensitivity to poor maternal nutrition during pregnancy, raising the risks for cognitive impairment later in life. This review explores how epigenetics induce and regulate critical periods, and also discusses how early environmental interactions prime a system towards a particular health outcome and influence susceptibility to disease or cognitive impairment throughout life.

Folic acid prevents habituation memory impairment and oxidative stress in an aging model induced by D-galactose

The present study aimed to evaluate the effect of folic acid treatment in an animal model of aging induced by D-galactose (D-gal). For this propose, adult male Wistar rats received D-gal intraperitoneally (100 mg/kg) and/or folic acid orally (5 mg/kg, 10 mg/kg or 50 mg/kg) for 8 weeks. D-gal caused habituation memory impairment, and folic acid (10 mg/kg and 50 mg/kg) reversed this effect. However, folic acid 50 mg/kg per se caused habituation memory impairment. D-gal increased the lipid peroxidation and oxidative damage to proteins in the prefrontal cortex and hippocampus from rats. Folic acid (5 mg/kg, 10 mg/kg, or 50 mg/kg) partially reversed the oxidative damage to lipids in the hippocampus, but not in the prefrontal cortex, and reversed protein oxidative damage in the prefrontal cortex and hippocampus. D-gal induced synaptophysin and BCL-2 decrease in the hippocampus and phosphorylated tau increase in the prefrontal cortex. Folic acid was able to reverse these D-gal-related alterations in the protein content. The present study shows folic acid supplementation as an alternative during the aging to prevent cognitive impairment and brain alterations that can cause neurodegenerative diseases. However, additional studies are necessary to elucidate the effect of folic acid in aging.

N-Methyl-D-Aspartate Receptor Signaling-Protein Kinases Crosstalk in Cerebral Ischemia

Although stroke is very often the cause of death worldwide, the burden of ischemic and hemorrhagic stroke varies between regions and over time regarding differences in prognosis, prevalence of risk factors, and treatment strategies. Excitotoxicity, oxidative stress, dysfunction of the blood-brain barrier, neuroinflammation, and lysosomal membrane permeabilization, sequentially lead to the progressive death of neurons. In this process, protein kinases-related checkpoints tightly regulate N-methyl-D-aspartate (NMDA) receptor signaling pathways. One of the major hallmarks of cerebral ischemia is excitotoxicity, characterized by overactivation of glutamate receptors leading to intracellular Ca²⁺ overload and ultimately neuronal death. Thus, reduced expression of postsynaptic density-95 protein and increased protein S-nitrosylation in neurons is responsible for neuronal vulnerability in cerebral ischemia. In this chapter death-associated protein kinases, cyclin-dependent kinase 5, endoplasmic reticulum stress-induced protein kinases, hyperhomocysteinemia-related NMDA receptor overactivation, ephrin-B-dependent amplification of NMDA-evoked neuronal excitotoxicity and lysosomocentric hypothesis have been discussed.Consequently, ample evidences have demonstrated that enhancing extrasynaptic NMDA receptor activity triggers cell death after stroke. In this context, considering the dual roles of NMDA receptors in both promoting neuronal survival and mediating neuronal damage, selective augmentation of NR2A-containing NMDA receptor activation in the presence of NR2B antagonist may constitute a promising therapy for stroke.

Elevated homocysteine, as a biomarker of cardiac injury, in panic disorder patients due to oxidative stress

BACKGROUND AND OBJECTIVE

Patients with panic disorder (PD) suffer from elevated oxidative stress as a consequence of serotonin metabolism disorder. These patients have elevated serotonin concentration and catabolism of serotonin via monoamine oxidase. The aim of the present study was to evaluate serum homocysteine concentration and its relationship with oxidative stress level in PD patients, regarding homocysteine as a diagnostic biomarker of heart disease.

MATERIALS & METHOD

Sixty patients with PD according to the DSM-5 diagnostic criteria for a panic attack and 60 healthy individuals were included in the present study. Peripheral venous blood samples were taken from patients. Erythrocytes and serum were separated from blood, and RBC hemolysates were prepared to investigate oxidative stress indices including glutathione and glutathione peroxidase. Serum homocysteine and carbonyl groups concentrations were measured in all samples. Data were analyzed using ANOVA, and p < .05 was considered significant.

RESULTS

Results showed that serum carbonyl groups concentration was significantly higher in patients with PD than in healthy individuals (p < .001). The results also indicated decreased serum glutathione concentration and glutathione peroxidase activity in patients (p < .003). In addition, elevated homocysteine concentration in PD patients serum was observed during the present study (p < .003).

CONCLUSION

Our findings support that patients with PD experience higher levels of oxidative stress, due to impaired serotonin metabolism, which is related to the prognosis of heart disease in these patients.

Gestational folate deficiency alters embryonic gene expression and cell function

Folic acid is a nutrient essential for embryonic development. Folate deficiency can cause embryonic lethality or neural tube defects and orofacial anomalies. Folate receptor 1 (Folr1) is a folate binding protein that facilitates the cellular uptake of dietary folate. To better understand the biological processes affected by folate deficiency, gene expression profiles of gestational day 9.5 (gd9.5) Folr1^-/- embryos were compared to those of gd9.5 Folr1^+/+ embryos. The expression of 837 genes/ESTs was found to be differentially altered in Folr1^-/- embryos, relative to those observed in wild-type embryos. The 837 differentially expressed genes were subjected to Ingenuity Pathway Analysis. Among the major biological functions affected in Folr1^-/- mice were those related to 'digestive system development/function', 'cardiovascular system development/function', 'tissue development', 'cellular development', and 'cell growth and differentiation', while the major canonical pathways affected were those associated with blood coagulation, embryonic stem cell transcription and cardiomyocyte differentiation (via BMP receptors). Cellular proliferation, apoptosis and migration were all significantly affected in the Folr1^-/- embryos. Cranial neural crest cells (NCCs) and neural tube explants, grown under folate-deficient conditions, exhibited marked reduction in directed migration that can be attributed, in part, to an altered cytoskeleton caused by perturbations in F-actin formation and/or assembly. The present study revealed that several developmentally relevant biological processes were compromised in Folr1^-/- embryos.

Chiroptical sensing of homocysteine

The cyclization reaction between ortho-phthalaldehyde and l-homocysteine coincides with the generation of a pronounced positive CD signal at approximately 335 nm. Under identical conditions, other amino acids including cysteine produce very weak CD responses. This unusual substrate specificity allows accurate chiroptical analysis of the enantiomeric composition of homocysteine samples in the presence of cysteine without the need for time-consuming chromatographic separation. This significantly simplifies and speeds up ee determination at reduced solvent waste production.

Role of homocysteine in the development and progression of Parkinson's disease

Homocysteine is an essential intermediate product of biochemical reactions that is present in various tissues of the human body. Homocysteine may be associated with the development and progression of Parkinson's disease. Plasma homocysteine levels in patients with Parkinson's disease are elevated compared to those of healthy individuals. High homocysteine drives PD development and progression while aggregating the clinical symptoms of PD patients. The relationship between PD and homocysteine involves multiple pathways, including nerve cell apoptosis, oxidative stress, and DNA damage. This is crucial for explaining how high homocysteine drives the PD procession. Elevated homocysteine level during PD development and progression offers a new strategy for the diagnosis and treatment of this disease.

The relationship of severity of depression with homocysteine, folate, vitamin B12, and vitamin D levels in children and adolescents

BACKGROUND

Depression is a heterogeneous disorder and is thought to develop as a result of complex interactions between genetic and environmental factors. One-carbon metabolism that includes vitamin B12, folic acid, and homocysteine has been investigated in psychiatric disorders like depression. In recent years, vitamin D has also been considered to contribute to psychiatric disorders. In this study, serum levels of folate, vitamin B12, and homocysteine related to one-carbon metabolism and vitamin D were investigated in children and adolescents with depression and to assess possible roles in depression pathogenesis.

METHODS

The study included 89 children and adolescents with depression (69 female, 20 male; mean age ± SD = 15.08 ± 1.46) and 43 control subjects (31 female, 12 male; mean age ± SD = 14.41 ± 2.32) without any DSM-5 diagnosis. Each subject completed a sociodemographic form, Childhood Depression Inventory, State-Trait Anxiety Inventory 1-2 and measured serum folate, vitamin B12, homocysteine, and 25-OH vitamin D levels.

RESULTS

There was no significant difference between the groups in terms of folate levels (p = .052). In the patient group, the vitamin B12 and vitamin D levels were clearly low (p values for both levels were <.001), while homocysteine levels were found to be remarkably high (p < .001). In addition, there was a negative correlation between depression severity and vitamin B12 and vitamin D, while a positive correlation was found with homocysteine.

CONCLUSIONS

The results of the study show that vitamin B12 deficiency or insufficiency and elevated homocysteine may contribute to the etiopathogenesis of depression. Additionally, it was shown that lower vitamin D levels may be associated with depression.

KEY PRACTITIONER MESSAGE

Depression of children and adolescents is associated with the interaction of environmental and genetic factors. Homocysteine, vitamin B12, and folate related to one-carbon metabolism are associated with psychiatric disorders such as depression in adulthood. Vitamin D also contributes to psychiatric disorders pathogenesis. There are not enough studies in the literature about these parameters in children with depression. Low vitamin B12 and vitamin D levels and increased homocysteine levels may play a role in the pathogenesis of depression in children and adolescents. Investigation of vitamin B12, folate, homocysteine, and vitamin D levels are recommended in children and adolescents with depression.

Influences of Folate Supplementation on Homocysteine and Cognition in Patients with Folate Deficiency and Cognitive Impairment

Although folate deficiency was reported to be associated with hyperhomocysteinemia, influence of folate supplementation on cognition remains controversial. Therefore, we explored the effects of folate supplementation on the cognition and Homocysteine (Hcy) level in relatively short periods in patients with folate deficiency and cognitive impairment. Enrolled 45 patients (mean age of 79.7 ± 7.9 years old) with folate deficiency (<3.6 ng/mL) with cognitive impairment underwent Mini-Mental State Examination (MMSE), and laboratory examinations, including folate, vitamin B₁₂, and Hcy. The degree of hippocampal atrophy in MRI was estimated using a voxel-based specific regional analysis system for Alzheimer’s disease (VSRAD). Patients were administrated folate (5 mg/day), then Hcy, and MMSE score were re-examined after 28 to 63 days. Mean Hcy significantly decreased from 25.0 ± 18.0 to 11.0 ± 4.3 nmol/mL (p < 0.001). Average MMSE scores also significantly changed from 20.1 ± 4.7 to 22.2 ± 4.3 (p < 0.001). The degree of change in the MMSE score and basic Hcy or Hcy change was significantly positively correlated, while degree of hippocampal atrophy in MRI did not. Although several factors should be taken into account, folate supplementation ameliorated cognitive impairment, at least for a short period, in patients with folate deficiency.

S-Adenosylmethionine Rescues Cognitive Deficits in the rTg4510 Animal Model by Stabilizing Protein Phosphatase 2A and Reducing Phosphorylated Tau

Background: Alterations in the methionine cycle and abnormal tau phosphorylation are implicated in many neurodegenerative diseases, including Alzheimer’s disease and frontotemporal dementia. rTg4510 mice express mutant human P301L tau and are a model of tau hyperphosphorylation. The cognitive deficit seen in these animals correlates with a burden of hyperphosphorylated tau and is a model to test therapies aimed at lowering phosphorylated tau. Objective: This study aimed to increase protein phosphatase 2A activity through supplementation of S-adenosylmethionine and analyze the effect on spatial memory and tau in treated animals. Methods: 6-month-old rTg4510 mice were treated with 100 mg/kg S-adenosylmethionine by oral gavage for 3 weeks. Spatial recognition memory was tested in the Y-maze. Alterations to phosphorylated tau and protein phosphatase 2A were explored using immunohistochemistry, western blot, and enzyme-linked immunosorbent assays. Results: Treatment with S-adenosylmethionine increased the Y-maze novel arm exploration time and increased both the expression and activity of protein phosphatase 2A. Furthermore, treatment reduced the number of AT8 positive neurons and reduced the expression of phosphorylated tau (Ser202/Thr205). S-adenosylmethionine contributes to multiple pathways in neuronal homeostasis and neurodegeneration. Conclusion: This study shows that supplementation with S-adenosylmethionine stabilizes the heterotrimeric form of PP2A resulting in an increase the enzymatic activity, a reduced level of pathological tau, and improved cognition.

Homocysteine induces melanocytes apoptosis via PERK-eIF2α-CHOP pathway in vitiligo

Vitiligo is a depigmentation disorder that develops as a result of the progressive disappearance of epidermal melanocytes. The elevated level of amino acid metabolite homocysteine (Hcy) has been identified as circulating marker of oxidative stress and known as a risk factor for vitiligo. However, the mechanism underlying Hcy-regulated melanocytic destruction is currently unknown. The present study aims to elucidate the effect of Hcy on melanocytic destruction and its involvement in the pathogenesis of vitiligo. Our results showed that Hcy level was significantly elevated in the serum of progressive vitiligo patients. Notably, Hcy induced cell apoptosis in melanocytes via activating reactive oxygen species (ROS) and endoplasmic reticulum (ER) stress protein kinase RNA-like ER kinase (PERK)-eukaryotic translation initiation factor 2α (eIF2α)-C/EBP homologous protein (CHOP) pathway. More importantly, folic acid, functioning in the transformation of Hcy, could lower the intracellular Hcy level and further reverse the apoptotic effect of Hcy on melanocytes. Additionally, Hcy disrupted melanogenesis whereas folic acid supplementation could reverse the melanogenesis defect induced by Hcy in melanocytes. Taken together, Hcy is highly increased in vitiligo patients at progressive stage, and our in vitro studies revealed that folic acid could protect melanocytes from Hcy-induced apoptosis and melanin synthesis inhibition, indicating folic acid as a potential benefit agent for patients with progressive vitiligo.

Maternal Dietary Factors and the Risk of Autism Spectrum Disorders: A Systematic Review of Existing Evidence

Prenatal maternal diet is a critical factor in offspring neurodevelopment. Emerging evidence suggests that prenatal diet may also play a role in the etiology autism spectrum disorder (ASD). This review summarizes studies published in English that examined prenatal nutrients or maternal diet in association with ASD from PubMed as of July 2020. Thiry-six studies from nine countries were included in this systematic review; these focused on multivitamin (n = 5), prenatal vitamin (n = 3), folic acid (FA; n = 14), Vitamin D (n = 11), polyunsaturated fatty acid or fish/supplement intake (n = 7), iron (n = 3), Vitamin B12 (n = 1), calcium (n = 1), magnesium (n = 1), and broad maternal dietary habits (n = 3). Overall, higher or moderate intake of prenatal/multivitamin, FA, and Vitamin D was associated with reductions in odds of ASD, though results have not been uniform and there is a need to clarify differences in findings based on biomarkers versus reported intake. Evidence was inconclusive or insufficient for other nutrients. Differences in the timing and measurement of these dietary factors, as well as potential residual confounding, may contribute to existing discrepancies. Key areas for future research to better understand the role of maternal diet in ASD include the need to address potential critical windows, examine the combined effect of multiple nutrients, and consider interactions with genetic or environmental factors. LAY SUMMARY: Maternal diet during pregnancy is important for child neurodevelopment. We reviewed 36 studies examining maternal diet and autism spectrum disorder (ASD) and found that prenatal vitamin/multivitamin use and adequate intake of folic acid and Vitamin D were each associated with lower likelihood of having a child with ASD. Future studies on these and other dietary factors are needed to better understand the role of maternal diet in the development of ASD. Autism Res 2020, 13: 1634-1658. © 2020 International Society for Autism Research and Wiley Periodicals LLC.

Association Between Cognitive Impairment and Vitamin B12, Folate, and Homocysteine Status in Elderly Adults: A Retrospective Study

BACKGROUND

Cognitive disorders in old age have a serious impact on the health and social aspects of patients and their families.

OBJECTIVE

The scope of this paper is to explore the role of cobalamin and folate that has been linked to cognitive decline, not only as a deficiency state depending on malnutrition, but also a determinant in cognitive impairment.

METHODS

A 6-year observational, retrospective study was conducted by collecting the routine blood analyses and cognitive screening scores of patients aged 60 years or older, followed at our Centre for the Diagnosis and Treatment of Cognitive Disorders.

RESULTS

In a linear regression with a multi-vitamin model, higher folate concentrations were correlated with better cognitive performances through MMSE score, even after correction for sex, age, and years of education (beta = 0.144, p = 0.001). Estimated MMSE marginal means for folate versus homocysteine showed that folate deficiency was associated with worse cognitive performances, with a more severe cognitive impairment when hyperhomocysteinemia was present.

CONCLUSION

The assessment of B-vitamin status among elderly adults can contribute to an economic and practical approach to the prevention and management of cognitive decline. Future studies focused to define optimal vitamin status are warranted.

Effects of Maternal Fish Oil and/or 5-Methyl-Tetrahydrofolate Supplementation during Pregnancy on Offspring Brain Resting-State at 10 Years Old: A Follow-Up Study from the NUHEAL Randomized Controlled Trial

Recent studies have shown that maternal supplementation with folate and long-chain polyunsaturated fatty acids (LC-PUFAs) during pregnancy may affect children's brain development. We aimed at examining the potential long-term effect of maternal supplementation with fish oil (FO) and/or 5-methyl-tetrahydrofolate (5-MTHF) on the brain functionality of offspring at the age of 9.5-10 years. The current study was conducted as a follow-up of the Spanish participants belonging to the Nutraceuticals for a Healthier Life (NUHEAL) project; 57 children were divided into groups according to mother's supplementation and assessed through functional magnetic resonance imaging (fMRI) scanning and neurodevelopment testing. Independent component analysis and double regression methods were implemented to investigate plausible associations. Children born to mothers supplemented with FO (FO and FO + 5-MTHF groups, n = 33) showed weaker functional connectivity in the default mode (DM) (angular gyrus), the sensorimotor (SM) (motor and somatosensory cortices) and the fronto-parietal (FP) (angular gyrus) networks compared to the No-FO group (placebo and 5-MTHF groups, n = 24) (PFWE < 0.05). Furthermore, no differences were found regarding the neuropsychological tests, except for a trend of better results in an object recall (memory) test. Considering the No-FO group, the aforementioned networks were associated negatively with attention and speed-processing functions. Mother's FO supplementation during pregnancy seems to be able to shape resting-state network functioning in their children at school age and appears to produce long-term effects on children´s cognitive processing.

Blood homocysteine levels in children with autism spectrum disorder: An updated systematic review and meta-analysis

Results of studies on peripheral blood levels of homocysteine (Hcy) in children with autism spectrum disorder (ASD) are inconsistent, and conclusions from two previous meta-analyses on this subject published in 2012 are already outdated. Therefore, we conducted an updated systematic review and meta-analysis to quantitatively summarize the peripheral blood Hcy data in children with ASD compared with healthy controls (HC). We searched PubMed, EMBASE, PsycINFO, PsycARTICLES, Web of Science, and Cochrane Library databases from inception to September 2019 for eligible studies, with no language restriction. Using random-effects model, we computed summary statistics. Thirty-one studies (3304 participants including 1641 cases) were included. The pooled results showed that the peripheral blood Hcy levels were significantly elevated in children with ASD when compared to HC (Hedges's g = 0.56, 95% CI = 0.36 to 0.76, P < 0.001). By sensitivity analyses, we confirmed that our results were quite robust. Additionally, no publication bias was observed in this meta-analysis. In conclusion, our study support the association of increased circulating Hcy levels with ASD in children, and the involvement of Hcy in the occurrence of ASD. However, in view of the significant between-study heterogeneity, the conclusions should be interpreted cautiously and more investigation is required.

Systemic vitamin intake impacting tissue proteomes

The kinetics and localization of the reactions of metabolism are coordinated by the enzymes that catalyze them. These enzymes are controlled via a myriad of mechanisms including inhibition/activation by metabolites, compartmentalization, thermodynamics, and nutrient sensing-based transcriptional or post-translational regulation; all of which are influenced as a network by the activities of metabolic enzymes and have downstream potential to exert direct or indirect control over protein abundances. Considering many of these enzymes are active only when one or more vitamin cofactors are present; the availability of vitamin cofactors likely yields a systems-influence over tissue proteomes. Furthermore, vitamins may influence protein abundances as nuclear receptor agonists, antioxidants, substrates for post-translational modifications, molecular signal transducers, and regulators of electrolyte homeostasis. Herein, studies of vitamin intake are explored for their contribution to unraveling vitamin influence over protein expression. As a body of work, these studies establish vitamin intake as a regulator of protein abundance; with the most powerful demonstrations reporting regulation of proteins directly related to the vitamin of interest. However, as a whole, the field has not kept pace with advances in proteomic platforms and analytical methodologies, and has not moved to validate mechanisms of regulation or potential for clinical application.

Pyridoxine Deficiency Exacerbates Neuronal Damage after Ischemia by Increasing Oxidative Stress and Reduces Proliferating Cells and Neuroblasts in the Gerbil Hippocampus

We investigated the effects of pyridoxine deficiency on ischemic neuronal death in the hippocampus of gerbil (n = 5 per group). Serum pyridoxal 5′-phosphate levels were significantly decreased in Pyridoxine-deficient diet (PDD)-fed gerbils, while homocysteine levels were significantly increased in sham- and ischemia-operated gerbils. PDD-fed gerbil showed a reduction in neuronal nuclei (NeuN)-immunoreactive neurons in the medial part of the hippocampal CA1 region three days after. Reactive astrocytosis and microgliosis were found in PDD-fed gerbils, and transient ischemia caused the aggregation of activated microglia in the stratum pyramidale three days after ischemia. Lipid peroxidation was prominently increased in the hippocampus and was significantly higher in PDD-fed gerbils than in Control diet (CD)-fed gerbils after ischemia. In contrast, pyridoxine deficiency decreased the proliferating cells and neuroblasts in the dentate gyrus in sham- and ischemia-operated gerbils. Nuclear factor erythroid-2-related factor 2 (Nrf2) and brain-derived neurotrophic factor (BDNF) levels also significantly decreased in PDD-fed gerbils sham 24 h after ischemia. These results suggest that pyridoxine deficiency accelerates neuronal death by increasing serum homocysteine levels and lipid peroxidation, and by decreasing Nrf2 levels in the hippocampus. Additionally, it reduces the regenerated potentials in hippocampus by decreasing BDNF levels. Collectively, pyridoxine is an essential element in modulating cell death and hippocampal neurogenesis after ischemia.

Implication of Hyperhomocysteinemia in Blood Retinal Barrier (BRB) Dysfunction

Elevated plasma homocysteine (Hcy) level, known as hyperhomocysteinemia (HHcy) has been linked to different systemic and neurological diseases, well-known as a risk factor for systemic atherosclerosis and cardiovascular disease (CVD) and has been identified as a risk factor for several ocular disorders, such as diabetic retinopathy (DR) and age-related macular degeneration (AMD). Different mechanisms have been proposed to explain HHcy-induced visual dysfunction, including oxidative stress, upregulation of inflammatory mediators, retinal ganglion cell apoptosis, and extracellular matrix remodeling. Our previous studies using in vivo and in vitro models of HHcy have demonstrated that Hcy impairs the function of both inner and outer blood retinal barrier (BRB). Dysfunction of BRB is a hallmark of vision loss in DR and AMD. Our findings highlighted oxidative stress, ER stress, inflammation, and epigenetic modifications as possible mechanisms of HHcy-induced BRB dysfunction. In addition, we recently reported HHcy-induced brain inflammation as a mechanism of blood–brain barrier (BBB) dysfunction and pathogenesis of Alzheimer’s disease (AD). Moreover, we are currently investigating the activation of glutamate receptor N-methyl-d-aspartate receptor (NMDAR) as the molecular mechanism for HHcy-induced BRB dysfunction. This review focuses on the studied effects of HHcy on BRB and the controversial role of HHcy in the pathogenesis of aging neurological diseases such as DR, AMD, and AD. We also highlight the possible mechanisms for such deleterious effects of HHcy.