The potential use of folate and its derivatives in treating psychiatric disorders: A systematic review

Folinic acid as a treatment for autism in children: A within-subjects open-label study on safety and efficacy

The folate cycle has been implicated in the pathophysiology of autism due to its role in the glutathione oxidative stress pathway, amino acid and DNA methylation reactions, and neurotransmitter synthesis pathway. Previous research on folinic acid supplementation in autistic children has suggested potential benefits. The primary aim of this pilot study was to determine the safety, feasibility and efficacy of oral folinic acid in improving communication and behaviour in autistic children. Ten autistic children were recruited into an open-label pre-post treatment within-subjects design study. At T = 0, 12 and 24 weeks, participants underwent safety evaluations, standardized assessments of language, autism symptoms, adaptive skills and global illness severity, and eye-gaze tracking. During the control period (0-12 weeks), participants continued with standard care. In the treatment period (12-24 weeks), participants took oral folinic acid at 2 mg/kg/day. All 10 children (nine boys, one girl; aged 4-8 years), successfully consumed oral folinic acid supplements with no adverse events. There was a reduction in Pervasive Developmental Disorder Behavior Inventory (PDDBI) Autism Composite T-score with treatment (mean [SD] T-score 49.2 [8.89] pre-treatment, 44.6 [6.19] post-treatment, p = 0.103). Although this difference was not statistically significant due to the small sample size, the effect size was medium-large, indicating that, as a group, there were clinically meaningful changes in PDDBI T-scores. There were also trends towards gains in communication scores and overall Clinical Global Impression scores. Folinic acid is a safe and feasible potential treatment for autism, and results from this pilot justify the need for a larger placebo-controlled trial.

Short report on a distinct electroencephalogram endophenotype for MTHFR gene variation co-occurring in autism spectrum disorder

LAY ABSTRACT

Methylenetetrahydrofolate reductase mutations refer to genetic variations in the methylenetetrahydrofolate reductase enzyme, which plays an important role in folate metabolism. Folate is essential for neural development and signalling. Children with autism spectrum disorder have atypical neural signals compared with control. This study used a non-invasive method to identify a distinct neural signal that may be useful in future screening for methylenetetrahydrofolate reductase mutation in children with autism spectrum disorder. Given that the underlying causes of autism spectrum disorder have multiple genetic factors and often require subjective assessment, this study introduces a potential non-invasive screening method for methylenetetrahydrofolate reductase gene mutation. This method could provide valuable biomarkers for screening and personalised treatments, offering hope for improved risk stratification and bespoke nutritional support and supplements to mitigate the impact on affected individuals and their descendants.

Circulating B vitamins metabolites in depressive disorders - connections with the microbiota-gut-brain axis

PURPOSE

In this review, we aim to summarize recent information about the association of B vitamins with immune-metabolic aspects of depression and their connection with the gut-brain axis.

VIEWS

B vitamins may alter depressive symptoms by many various mechanisms such as reducing oxidative stress, inflammation, gut permeability, controlling epigenetics, modifying the microbiome, and stimulating it to produce many beneficial substances such as short-chain fatty acids or neurotransmitters: norepinephrine, dopamine, serotonin, gamma-aminobutyric acid, and acetylcholine.

CONCLUSIONS

Specifically, vitamins B1 (thiamine), B6 (pyridoxine), B9 (folate), and B12 (cyanocobalamin), B2 (riboflavin) have been observed to affect depression. Given probiotic's capability to produce vitamins from the B group, and modify intestinal function, inflammation, or metabolic dysfunction, their supplementation might be a possible treatment method for the immunometabolic form of depression. Thus, the intake of certain probiotic bacterial strains simultaneously with controlling the required daily intake of B vitamins may positively affect the course of depression. Circulating B vitamins metabolite levels, especially B9, B12, and B6 may also be biomarkers of depression. Further investigation is needed to find stronger evidence on this topic.

Treatments in the pipeline for attention-deficit/hyperactivity disorder (ADHD) in adults

To provide an overview of treatments in the pipeline for adults with attention-deficit/hyperactivity disorder (ADHD), we searched https://clinicaltrials.gov/and and https://www.clinicaltrialsregister.eu/ from 01/01/2010-10/18/2023 for ongoing or completed phase 2 or 3 randomised controlled trials (RCTs), assessing pharmacological or non-pharmacological interventions for adults with ADHD with no current regulatory approval. We found 90 eligible RCTs. Of these, 24 (27 %) reported results with statistical analysis for primary efficacy endpoints. While several pharmacological and non-pharmacological interventions had evidence of superiority compared to the control condition from a single RCT, centanafadine (norepinephrine, dopamine, and serotonin re-uptake inhibitor) was the only treatment with evidence of efficacy on ADHD core symptoms (small effect size=0.28-0.40) replicated in at least one additional RCT, alongside reasonable tolerability. Overall, the body of ongoing RCTs in adults with ADHD is insufficient, without any intervention on the horizon to match the efficacy of stimulant treatment or atomoxetine and with better tolerability profile. Additional effective and well tolerated treatments for adults with ADHD require development and testing.

Investigating the Impacts of Diet, Supplementation, Microbiota, Gut-Brain Axis on Schizophrenia: A Narrative Review

Schizophrenia is a disease with a complex etiology that significantly impairs the functioning of patients. In recent years, there has been increasing focus on the importance of the gut microbiota in the context of the gut-brain axis. In our study, we analyzed data on the gut-brain axis in relation to schizophrenia, as well as the impacts of eating habits, the use of various supplements, and diets on schizophrenia. Additionally, the study investigated the impact of antipsychotics on the development of metabolic disorders, such as diabetes, dyslipidemia, and obesity. There may be significant clinical benefits to be gained from therapies supported by supplements such as omega-3 fatty acids, B vitamins, and probiotics. The results suggest the need for a holistic approach to the treatment of schizophrenia, incorporating both drug therapy and dietary interventions.

Folic acid and autism: updated evidences

Autism spectrum disorder (ASD) is a complex neurodevelopmental condition that impairs communication, socialization, and behavior. The association of ASD with folic acid has been investigated due to the importance of this vitamin for neurological health. This study is an update of the publication 'Folic acid and autism: What do we know?' and aims to systematically review studies examining the relationship between folic acid and ASD. The search resulted in 2,389 studies on folic acid and ASD, which were selected by two reviewers based on their titles and abstracts. Studies meeting the inclusion criteria were fully read. The 52 included studies involved 10,429 individuals diagnosed with ASD and assessed the intake of vitamin B6, folic acid, and vitamin B12; serum levels of these vitamins, homocysteine, and methionine; therapeutic interventions using folic acid; and the association between maternal exposure to this vitamin and the risk of ASD. The evidence of insufficient folic acid intake in most individuals with ASD remains consistent in this update. No association was found between maternal exposure to folic acid and the risk of ASD in their children. Despite observed improvements in communication, socialization, and behavior in individuals with ASD following folic acid interventions, it is crucial to consider the individuality and complexity of ASD. Given the relevance of the topic, there remains a need for more high-quality research and clinical trials characterized by rigorous methodological designs.

Co-Occurring Methylenetetrahydrofolate Reductase (MTHFR) rs1801133 and rs1801131 Genotypes as Associative Genetic Modifiers of Clinical Severity in Rett Syndrome

AIM

Remethylation disorders such as 5,10-methylenetetrahydrofolate reductase (MTHFR) deficiency reduce the remethylation of homocysteine to methionine. The resulting hyperhomocysteinemia can lead to serious neurological consequences and multisystem toxicity. The role of MTHFR genotypes has not been investigated in patients with Rett Syndrome (RTT). In this study, we sought to assess the impact of co-occurring MTHFR genotypes on symptom profiles in RTT.

METHOD

Using pharmacogenomic (PGx) testing, the MTHFR genetic polymorphisms rs1801133 (c.665C>T mutation) and rs1801131 (c.1286A>C mutation) were determined in 65 patients (18.7 years ± 12.1 [mean ± standard deviation]) with RTT as part of routine clinical care within the Centre for Interventional Paediatric Psychopharmacology (CIPP) Rett Centre, a National and Specialist Child and Adolescent Mental Health Service (CAMHS) in the UK. The clinical severity of patients was assessed using the RTT-anchored Clinical Global Impression Scale (RTT-CGI).

RESULTS

The clinical severity symptom distribution varied between the homozygous and heterozygous MTHFR rs1801133 and rs1801131 genotypes. Those with the homozygous genotype had a narrower spread of severity scores across several domains (language and communication, ambulation, hand-use and eye contact clinical domains). Patients with the homozygous genotype had statistically significantly greater CGI-Severity scores than individuals with a non-homozygous MTHFR genotype (Z = -2.44, p = 0.015). When comparing the ratings of moderately impaired (4), markedly impaired (5), severely impaired (6) and extremely impaired (7), individuals with the homozygous MTHFR genotype were more impaired than those with the non-homozygous MTHFR genotype (Z = -2.06, p = 0.039). There was no statistically significant difference in the number of prescribed anti-epileptic drugs between the genotypes.

CONCLUSIONS

Our findings show that in those with a pathogenic RTT genetic variant, co-occurring homozygotic MTHFR rs1801133 and rs1801131 polymorphisms may act as associative genetic modifiers of clinical severity in a subset of patients. Profiling of rs1801133 and rs1801131 in RTT may therefore be useful, especially for high-risk patients who may be at the most risk from symptom deterioration.

Improving drug delivery to the brain: the prodrug approach

INTRODUCTION

The prodrug approach has been thought to be a simple solution to improve brain drug delivery for decades. Nevertheless, it still comes as a surprise that there is relatively little success in the field. The best example anti-parkinsonian drug levodopa has been serendipitously discovered to be a transporter-utilizing brain-delivered prodrug rather than a rationally developed one.

AREAS COVERED

The lack of success can mainly be explained by the insufficient understanding of the role of membrane proteins that can facilitate drug delivery at dynamic barriers, such as the blood-brain barrier (BBB), but also by the sparse knowledge of prodrug bioconverting enzymes in the brain. This review summarizes the current status of the prodrug attempts that have been developed in the past to improve brain drug delivery.

EXPERT OPINION

With the expandingly improved analytical and computational technologies, it is anticipated that enhanced brain drug delivery will be eventually achieved for most of the central nervous system (CNS) acting drugs. However, this requires that carrier-mediated (pro)drug delivery methods are implemented in the very early phases of the drug development processes and not as a last step to survive a problematic investigational drug candidate.

Folate and Its Significance in Depressive Disorders and Suicidality: A Comprehensive Narrative Review

Depressive disorders pose significant challenges to global public health, necessitating effective prevention and management strategies. Notably, the occurrence of suicide frequently coincides with depressive episodes. Suicide is as a paramount global health concern that demands efficacious preventive strategies. Current psychiatric approaches heavily rely on pharmacological interventions but have had limited success in addressing the global burden of mental health issues. Suboptimal nutrition, with its impact on the neuroendocrine system, has been implicated in the underlying pathology of depressive disorders. Folate, a group of water-soluble compounds, plays a crucial role in various central nervous system functions. Depressed individuals often exhibit low levels of serum and red blood cell folate. Multiple studies and systematic reviews have investigated the efficacy of folic acid and its derivative, L-methylfolate, which can cross the blood-brain barrier, as stand-alone or adjunct therapies for depression. Although findings have been mixed, the available evidence generally supports the use of these compounds in depressed individuals. Recent studies have established links between the one-carbon cycle, folate-homocysteine balance, immune system function, glutamate excitation via NMDA (N-methyl-D-aspartate) receptors, and gut microbiome eubiosis in mood regulation. These findings provide insights into the complex neurobiological mechanisms underlying the effects of folate and related compounds in depression. Through a comprehensive review of the existing literature, this study aims to advance our understanding of the therapeutic potential of folic acid and related compounds in depression treatment. It also seeks to explore their role in addressing suicidal tendencies and shed light on the neurobiological mechanisms involved, leveraging the latest discoveries in depression research.

The Association Between MTHFR C677T Gene Polymorphism and Repeated Pregnancy Loss in Arabic Countries: a Systematic Review and Meta-Analysis

The role of MTHFR C677T polymorphism in repeated pregnancy loss (RPL) among different populations has been studied with inconsistent results. The study objective was to determine the association between MTHFR C677T polymorphisms and RPL among Arab women. The review included all the available studies investigating the association between MTHFR C677T polymorphism and RPL from 2000 until now. The searched database included Cochrane, Trip, EMBASE, and Google Scholar. Two authors independently reviewed the searched articles for eligibility, judged their risk of bias, and extracted the characteristics of the studies. Review Manager 5.3 program was used for data analysis using odds ratio (OR) at a 95% confidence interval (CI). The study revealed a statistically significant difference between cases and controls regarding combined MTHFR C677T polymorphisms (OR = 1.50, 95% CI = 1.15-1.96), MTHFR C677T heterozygous (OR = 1.41, 95% CI = 1.08-1.83), and MTHFR C677T homozygous (OR = 4.19, 95% CI = 1.87-9.39). Considerable significant heterogeneity was recorded in the three analyses (P < 0.05). The review supported the hypothesis that MTHFR C677T mutation is considered a significant risk factor for RPL among Arab women.

Genome-Environment Interactions and Psychiatric Disorders

Environmental factors are known to interact with the genome by altering epigenetic mechanisms regulating gene expression and contributing to the pathogenesis of psychiatric disorders. This article is a narrative review of how the major environmental factors contribute to the pathogenesis of common psychiatric disorders such as schizophrenia, bipolar disorder, major depressive disorder, and anxiety disorder this way. The cited articles were published between 1 January 2000 and 31 December 2022 and were obtained from PubMed and Google Scholar. The search terms used were as follows: gene or genetic; genome; environment; mental or psychiatric disorder; epigenetic; and interaction. The following environmental factors were found to act epigenetically on the genome to influence the pathogenesis of psychiatric disorders: social determinants of mental health, maternal prenatal psychological stress, poverty, migration, urban dwelling, pregnancy and birth complications, alcohol and substance abuse, microbiota, and prenatal and postnatal infections. The article also discusses the ways by which factors such as drugs, psychotherapy, electroconvulsive therapy, and physical exercise act epigenetically to alleviate the symptoms of psychiatric disorders in affected patients. These data will be useful information for clinical psychiatrists and those researching the pathogenesis and treatment of psychiatric disorders.

Appropriate Macronutrients or Mineral Elements Are Beneficial to Improve Depression and Reduce the Risk of Depression

Depression is a common mental disorder that seriously affects the quality of life and leads to an increasing global suicide rate. Macro, micro, and trace elements are the main components that maintain normal physiological functions of the brain. Depression is manifested in abnormal brain functions, which are considered to be tightly related to the imbalance of elements. Elements associated with depression include glucose, fatty acids, amino acids, and mineral elements such as lithium, zinc, magnesium, copper, iron, and selenium. To explore the relationship between these elements and depression, the main literature in the last decade was mainly searched and summarized on PubMed, Google Scholar, Scopus, Web of Science, and other electronic databases with the keywords "depression, sugar, fat, protein, lithium, zinc, magnesium, copper, iron, and selenium". These elements aggravate or alleviate depression by regulating a series of physiological processes, including the transmission of neural signals, inflammation, oxidative stress, neurogenesis, and synaptic plasticity, which thus affect the expression or activity of physiological components such as neurotransmitters, neurotrophic factors, receptors, cytokines, and ion-binding proteins in the body. For example, excessive fat intake can lead to depression, with possible mechanisms including inflammation, increased oxidative stress, reduced synaptic plasticity, and decreased expression of 5-Hydroxytryptamine (5-HT), Brain Derived Neurotrophic Factor (BDNF), Postsynaptic density protein 95(PSD-95), etc. Supplementing mineral elements, such as selenium, zinc, magnesium, or lithium as a psychotropic medication is mostly used as an auxiliary method to improve depression with other antidepressants. In general, appropriate nutritional elements are essential to treat depression and prevent the risk of depression.

Methyl Donors, Epigenetic Alterations, and Brain Health: Understanding the Connection

Methyl donors such as choline, betaine, folic acid, methionine, and vitamins B6 and B12 are critical players in the one-carbon metabolism and have neuroprotective functions. The one-carbon metabolism comprises a series of interconnected chemical pathways that are important for normal cellular functions. Among these pathways are those of the methionine and folate cycles, which contribute to the formation of S-adenosylmethionine (SAM). SAM is the universal methyl donor of methylation reactions such as histone and DNA methylation, two epigenetic mechanisms that regulate gene expression and play roles in human health and disease. Epigenetic mechanisms have been considered a bridge between the effects of environmental factors, such as nutrition, and phenotype. Studies in human and animal models have indicated the importance of the optimal levels of methyl donors on brain health and behavior across the lifespan. Imbalances in the levels of these micronutrients during critical periods of brain development have been linked to epigenetic alterations in the expression of genes that regulate normal brain function. We present studies that support the link between imbalances in the levels of methyl donors, epigenetic alterations, and stress-related disorders. Appropriate levels of these micronutrients should then be monitored at all stages of development for a healthier brain.

Folate in maternal rheumatoid arthritis-filial autism spectrum disorder continuum

Rheumatoid Arthritis (RA) is an inflammatory autoimmune disease that affects women three times more than men. Epidemiological studies found that the incidence of Autism Spectrum Disorder (ASD), a neurological and developmental disorder, in children born to mothers suffering from RA is higher compared with the control population. Considering that the pathogenesis of ASD could be traced back to pregnancy and in uterine conditions, and the evidence of reduced folate levels in the brain of ASD-affected children, we aimed to study the role of folate, as an important nutritional factor during pregnancy, in associating maternal RA to ASD development in the offspring. Folate balance during RA could be influenced twice, initially during the immune activation associated with disease onset, and later during the treatment with anti-folate drugs, with a potential consequence of folate deficiency. Maternal folate deficiency during pregnancy could increase homocysteine levels, oxidative stress, and global DNA hypomethylation, all known risk factors in ASD pathogenesis. These effects could be intensified by genetic polymorphisms in the folate system, which were also found as genetic risk factors for both RA and ASD. The available evidence suggests that folate level as an important factor during RA, pregnancy and ASD could have pathological and therapeutical significance and should be carefully monitored and investigated in the RA-pregnancy-ASD axis.

Identification of Genetic Variations in the NAD-Related Pathways for Patients with Major Depressive Disorder: A Case-Control Study in Taiwan

Background and Objectives: Nicotinamide adenine dinucleotide (NAD) is an important coenzyme in various physiological processes, including sirtuins (SIRTs) and kynurenine pathway (KP). Previous studies have shown that lower NAD levels can be indicative of increased risks of cancer and psychiatric disorders. However, there has been no prior study exploring the link between NAD homeostasis and psychiatric disorders from a genetic perspective. Therefore, we aimed to investigate the association of genetic polymorphism in the pathways of NAD biosynthesis with major depressive disorder (MDD). Methods: A total of 317 patients were included in the case group and were compared with sex-matched control group of 1268 participants (1:4 ratio) from Taiwan Biobank (TWB). All subjects in the control group were over 65 years old, which is well past the average age of onset of MDD. Genomic DNA extracted from patients' blood buffy coat was analyzed using the Affymetrix TWB array. Full-model tests were conducted for the analysis of single nucleotide polymorphism (SNPs) in all candidate genes. We focused on genes within the NAD-related candidate pathways, including 15 in KP, 12 in nicotinate metabolism, 7 in SIRTs, and 19 in aldehyde dehydrogenases (ALDHs). A total of 508 SNPs were analyzed in this study. After significant SNPs were determined, 5000 genome-wide max(T) permutations were performed in Plink. Finally, we built a predictive model with logistic regression and assessed the interactions of SNPs with the haplotype association tests. Results: We found three SNPs that were significantly associated with MDD in our NAD-related candidate pathways, one within the KP (rs12622574 in ACMSD) and two within the nicotinate metabolism (rs28532698 in BST1 and rs3733593 in CD38). The observed association with MDD was significant in the dominant model of inheritance with marital status, education level, and body mass index (BMI) adjusted as covariates. Lastly, in haplotype analysis, the three associated SNPs consisted of one haploblock in ACMSD, four haploblocks in BST1, and two haploblocks in CD38. Conclusions: This study provides the first evidence that genetic variations involved in NAD homeostasis in the KP and nicotinate metabolism may be associated with the occurrence of MDD.

Synergic action of L-acetylcarnitine and L-methylfolate in Mouse Models of Stress-Related Disorders and Human iPSC-Derived Dopaminergic Neurons

The epigenetic agents, L-acetylcarnitine (LAC) and L-methylfolate (MF) are putative candidates as add-on drugs in depression. We evaluated the effect of a combined treatment with LAC and MF in two different paradigms of chronic stress in mice and in human inducible pluripotent stem cells (hiPSCs) differentiated into dopaminergic neurons. Two groups of mice were exposed to chronic unpredictable stress (CUS) for 28 days or chronic restraint stress (CRS) for 21 day, and LAC (30 or 100 mg/kg) and/or MF (0.75 or 3 mg/kg) were administered i.p. once a day for 14 days, starting from the last week of stress. In both stress paradigms, LAC and MF acted synergistically in reducing the immobility time in the forced swim test and enhancing BDNF protein levels in the frontal cortex and hippocampus. In addition, LAC and MF acted synergistically in enhancing type-2 metabotropic glutamate receptor (mGlu2) protein levels in the hippocampus of mice exposed to CRS. Interestingly, CRS mice treated with MF showed an up-regulation of NFκB p65, which is a substrate for LAC-induced acetylation. We could also demonstrate a synergism between LAC and MF in cultured hiPSCs differentiated into dopamine neurons, by measuring dendrite length and number, and area of the cell soma after 3 days of drug exposure. These findings support the combined use of LAC and MF in the treatment of MDD and other stress-related disorders.