Vitamin B12 , folate, and the methionine remethylation cycle-biochemistry, pathways, and regulation

The role of branched chain aminotransferase in the interrelated pathways of type 2 diabetes mellitus and Alzheimer's disease

Objectives

This review assessed the role of Branched-Chain Amino Acid Transaminase (BCAT) enzymes in human metabolism, and their involvement in the catabolism of branched-chain amino acids (BCAAs) and exploring the association between Type 2 Diabetes Mellitus (T2DM) and Alzheimer's disease (AD) through insulin resistance.

Methods

The analysis involves a comprehensive literature review of recent research findings related to BCAT enzymes, BCAA metabolism, T2DM, and AD. Relevant studies and articles were identified through systematic searches in databases such as PubMed, ScienceDirect, and other scholarly resources. Inclusion criteria encompassed research articles, reviews, and studies published in peer-reviewed journals, with a focus on human metabolism, BCAT enzymes, and the interplay between BCAA metabolism, T2DM, and AD.

Results

The association between T2DM and AD suggests a potential metabolic link, particularly through dysregulated BCAA metabolism leading to insulin resistance. The impact of impaired insulin signaling is implicated in brain function and the accumulation of amyloid plaques facilitated by BCAT.

Conclusion

The identified link between BCAT, BCAA metabolism, T2DM, and AD suggests that disruptions in BCAT levels could serve as valuable indicators for early detection of insulin resistance and cognitive impairment as observed in Type 3 Diabetes which may present a promising therapeutic target.

Vitamins and dietary supplements in cancer treatment: is there a need for increased usage?

INTRODUCTION

Vitamins are essential for homeostasis and proper functioning of organisms. These micronutrients prevent tumor onset by functioning as antioxidants and enzymatic cofactors involved in anti-stress and immune responses, modulating epigenetic regulators, and shaping the microbiota composition. Unbalanced diets and sedentary lifestyles contribute to obesity, associated with increasing cancer risk. Cancer patients often exhibit vitamin deficiencies due to chronic inflammation, anticancer therapies, and tumor-induced metabolic changes, leading to malnutrition and cachexia.

AREAS COVERED

This review critically analyzes preclinical and clinical studies, sourced from PubMed and ClinicalTrials.gov databases, that investigate the potential benefits of vitamin supplementation and dietary interventions, such as intermittent fasting and ketogenic diets, in mouse tumor models and cancer patients. This analysis elucidates the limitations of such interventions and suggests optimal dietary strategies to prevent cancer and enhance patients' quality of life and prognosis.

EXPERT OPINION

To date, clinical studies have found no substantial benefit of over-the-counter vitamin supplements and dietary interventions on cancer patients' health and prognosis. To prevent the spread of useless and potentially harmful products by the nutraceutical industry, establishing a regulatory authority is necessary to monitor and ensure product quality and validity before commercialization.

DmdA-independent lag phase shortening in Phaeobacter inhibens bacteria under stress conditions

Bacteria can shorten their lag phase by using methyl groups from compounds like dimethylsulfoniopropionate (DMSP), which are incorporated into cellular components via the methionine cycle. However, the role of specific methionine synthases in this process is not fully understood. Using transcriptomics, genetics, and biochemical assays, we investigated methionine synthases involved in lag phase shortening in Phaeobacter inhibens. We focused on a cobalamin-dependent methionine synthase (MetH)-like complex encoded by three genes: a betaine-homocysteine S-methyltransferase (bmt), a cobalamin-binding protein (cbp), and an intermediate methyl carrier (PGA1_c16040). Expression profiling revealed transcriptional decoupling among these genes. Deleting bmt disrupted lag phase shortening in response to DMSP. Functional assays showed that Bmt can directly produce methionine from DMSP and betaine, independent of tetrahydrofolate (THF) or cobalamin. Interestingly, under stress conditions, lag phase shortening occurred even in the absence of dimethylsulfoniopropionate demethylase DmdA, the primary DMSP demethylase. Under osmotic and oxidative stress, bmt expression increased significantly in response to both DMSP and betaine, suggesting an alternative methylation route. This highlights the role of Bmt as both demethylase and a methionine synthase under stress, offering a cost-effective strategy for methyl group assimilation. Our findings reveal a novel stress-responsive pathway for methionine synthesis and demonstrate the role of Bmt in promoting bacterial adaptation by accelerating the lag phase.

A Study of Body Composition in Children Suffering From Infantile Vitamin B12 Deficiency

BACKGROUND

Infantile tremor syndrome (ITS), or neurocutaneous infantile vitamin B12 deficiency syndrome (NIBS), is characterised by tremors, developmental delay, anaemia and skin hyperpigmentation. This study aimed to assess the body composition and serum lipids in children with ITS.

METHODS

Children under 2 years of age with a clinical diagnosis of ITS were enrolled. Dietary history, developmental milestones and anthropometric data were recorded, along with blood tests for B12, homocysteine, lipid profile and blood counts.

RESULTS

Of 50 children screened, 31 with a median age of 13 months were included. Most (80.6%) were from lower socio-economic backgrounds. Limb tremors were observed in 51.6%, and all but one child had a developmental quotient (DQ) below 70, indicating significant developmental delays. Microcephaly was present in 35.4%, and moderate to severe anaemia was nearly universal. Growth parameters, including fat mass and fat-free mass, were significantly lower in children with ITS compared to controls. Lipid profiles revealed consistently high triglycerides, low HDL and elevated LDL in most age groups, suggesting a pro-atherogenic metabolic state.

CONCLUSION

Severe Infantile vitamin B12 deficiency significantly impairs head growth, overall development and body composition, with potential long-term cardiovascular risks due to abnormal lipid profiles.

Interaction of Genetics and Dietary Patterns Scored by the High Healthy Eating Index in Hyperhomocysteinaemia Influencing Cardiovascular Disease Risk

Hyperhomocysteinaemia has been associated with increased cardiovascular disease (CVD) risk, but the complex interplay between genetic determinants and modifiable lifestyle factors in modulating homocysteine (HC) levels remains incompletely understood. We aimed to investigate the aetiology of hyperhomocysteinaemia by examining the interactions between genetic predisposition, dietary patterns and other lifestyle factors and their potential associations with metabolic syndrome (MetS) and CVD risk. Cross-sectional analysis from the Korean Genome and Epidemiology Study, a hospital-based cohort conducted by the Korean Centers for Disease Control and Prevention from 2012 to 2016. Korean adults (n = 62 743, aged 40-79 years) were categorised into Low-HC (n = 53 450) and High-HC (n = 9293) groups based on a 15 μM serum homocysteine cutoff. Demographic, anthropometric and biochemical data were analysed. Genome-wide association and gene-environment interaction models explored genetic variants influencing hyperhomocysteinaemia and their interplay with lifestyle factors, including nutrient intake. Multivariable logistic regression assessed associations between hyperhomocysteinaemia and metabolic/CVD risks, adjusting for covariates. Genetic variant-environment interaction analyses identified genetic determinants and their interactions with diet/lifestyle. The High-HC group exhibited an elevated MetS risk. Hyperhomocysteinaemia was correlated with liver damage, inflammation and CVD risks. Low vitamin B12 intake (< 5.4 μg/day) showed a stronger association with hyperhomocysteinaemia than low folate intake (< 350 μg/day), with combined deficiencies exacerbating hyperhomocysteinaemia. An inverse relationship was observed between hyperhomocysteinaemia and healthy eating indices like Asian balanced and plant-based diets. Variants in MTHFR, NOX4, PLOD1, MIIP, PAX6 and CBS genes, involved in methionine/cysteine metabolism, exhibited differential expression in skeletal muscle, liver and adipose tissues. High polygenic risk scores interacted with poor diet quality, excess energy intake, a high glycemic index, smoking and heavy alcohol consumption to contribute to hyperhomocysteinaemia. In conclusion, these findings elucidate the complex interplay between genetics, diet and lifestyle in modulating homocysteine levels, providing insights for personalised nutrition strategies to mitigate CVD risk.

Molecular Alterations in Gastric Intestinal Metaplasia Shed Light on Alteration of Methionine Metabolism: Insight into New Diagnostic and Treatment Approaches

Gastric intestinal metaplasia (GIM) is a precancerous lesion and the key risk factor in the development of gastric cancer (GC), but early detection and treatment remain challenging. The traditional endoscopic diagnosis of metaplastic lesions is complicated by an increased rate of inappropriateness and false negativity. Although early interventions with H. pylori eradication, as well as endoscopic therapy results, were promising, there is still a significant unmet need to control GIM progression and recurrences. Molecular alterations, such as an increased DNA methylation index, have been identified as a crucial factor in the downregulation of tumor suppressor genes, such as the caudal-type homeobox (CDX2) gene, which regulates epithelial cell proliferation and GIM progression and is associated with treatment failure. CDX2 is downregulated by promoter hypermethylation in the colonic-type epithelium, in which the methylation was correlated with reduced intake of dietary folate sources. Tumor cells alter to dietary methionine sources in the biosynthesis of S-Adenosylmethionine, a universal methyl donor for transmethylation, under the conditions of limited folate and B12 availability. The gut microbiota also exhibited a shift in microbial composition, which could influence the host's dietary methionine metabolism. Meanwhile, activated oncogenic signaling via the PI3K/Akt/mTORC1/c-MYC pathway could promotes rewiring dietary methionine and cellular proliferation. Tumor methionine dependence is a metabolic phenotype that could be helpful in predictive screening of tumorigenesis and as a target for preventive therapy to enhance precision oncology. This review aimed to discuss the molecular alterations in GIM to shed light on the alteration of methionine metabolism, with insight into new diagnostic and treatment approaches and future research directions.

MTHFR Gene Polymorphisms: A Single Gene with Wide-Ranging Clinical Implications-A Review

The enzyme 5,10-methylenetetrahydrofolate reductase (MTHFR) catalyzes the conversion of 5,10-methylenetetrahydrofolate to 5-methyltetrahydrofolate, a process essential for the methylation of homocysteine to methionine. Polymorphisms in the MTHFR gene can reduce enzyme activity, disrupting the folate cycle and leading to hyperhomocysteinemia. The two most common polymorphisms associated with this gene are 667C>T (rs1801133) and 1298A>C (rs1801131). Background: This review provides a comprehensive summary of the current knowledge regarding MTHFR polymorphisms, with a particular focus on their potential impact on disease susceptibility. We hope this review will serve as a valuable resource for understanding the significance of MTHFR polymorphisms and their complex relationships with various diseases. Methods: For this review, we prioritized recent evidence, focusing on reviews and meta-analyses published between 2015 and 2025, sourced from PubMed and Google Scholar. Results: We explore the connection between these polymorphisms and a broad spectrum of medical conditions, including cardiovascular diseases and oxidative stress pathology; neurological and psychiatric disorders, such as Autism Spectrum Disorder, Alzheimer's disease, Schizophrenia, and Major Depressive Disorder; fertility, pregnancy, and neonatal complications, including recurrent pregnancy loss, pre-eclampsia, preterm birth, low birth weight, and neural tube defects; metabolic disorders, such as diabetes mellitus, inflammatory bowel disease, and non-alcoholic fatty liver disease; and oncological conditions, including breast, prostate, and ovarian cancers; as well as leukemia, and autoimmune diseases, particularly rheumatoid arthritis. Conclusions: While some diseases have a well-established association with MTHFR polymorphisms, others require further investigation. Our analysis highlights the crucial role of environmental factors, such as ethnic background and dietary folate intake, in influencing study outcomes.

The Role of Cobalamin in Multiple Sclerosis: An Update

Multiple sclerosis (MS) is a neurodegenerative condition that results in axonal and permanent damage to the central nervous system, necessitating healing owing to autoimmune reactions and persistent neuroinflammation. Antioxidant and anti-inflammatory drugs are essential for the management of oxidative stress and neuroinflammation. Additionally, multivitamin supplementation, particularly vitamin B12 (cobalamin), may be beneficial for neuronal protection. Although there is no documented connection between vitamin B12 deficiency and MS, researchers have explored its potential as a metabolic cause. This review highlights the therapeutic benefits of cobalamin (Cbl) in patients with MS.

Choline metabolism in ischemic stroke: An underappreciated "two-edged sword"

Ischemic stroke (IS) is an important cause of death and disability worldwide, but the molecular mechanisms involved are not fully understood. In this context, choline metabolism plays an increasingly important role in IS due to its multifaceted mechanisms involving neuroprotection, neuroregeneration, inflammatory response, immune regulation, and long-term health effects. With the deepening of the research on choline and its metabolites, such as trimethylamine-N-oxide (TMAO), scientists have gradually realized its key role in the occurrence, development and potential treatment of IS. This review summarizes the importance of choline in neuroprotection and long-term disease management, highlighting the complexity of choline metabolism affecting cerebrovascular health through gut microbes. Although choline and its metabolites exhibit a protective effect, excessive intake and increases in some metabolites may confer risk, suggesting the need to carefully balance dietary choline intake. The purpose of this review is to integrate the existing research results and provide a theoretical basis for further exploring the mechanism, prognosis evaluation and clinical intervention of choline metabolism in ischemic IS, hoping to provide a new perspective and enlightenment for the formulation of effective stroke prevention and treatment strategies, and promote a comprehensive understanding of heart and brain health and optimize intervention methods.

Lettuce fortification through vitamin B12-producing bacteria - proof of concept study

BACKGROUND

Vitamin B12 (cobalamin) can be produced de novo only by certain bacteria and archaea. It plays a crucial role in the health of animals and humans, which obtain it only through diet, mainly from animal products. This study aimed to identify endophytic bacterial strains capable of synthesizing vitamin B12 and enriching edible plants with it as a potential solution for vitamin B12 deficiency in vegetarians, vegans, and people with poor diets.

RESULTS

An in silico genome analysis was performed on 66 bacterial genomes, including the reference strain Pseudomonas denitrificans ATCC 13867, a known vitamin B12 producer. The genomes were analyzed using the Rapid Annotations using Subsystems Technology (RAST) server and the MetaCyc database to verify the presence and completeness of the vitamin B12 metabolic pathway. The ability of the strains to produce vitamin B12 was confirmed with a high-performance liquid chromatography with diode-array detection (HPLC-DAD) analysis of pure culture extracts. Eleven strains produced detectable amounts of vitamin B12 under tested conditions. The best performing candidates were further tested for their efficacy in producing vitamin B12 in lettuce grown under sterile conditions on Murashige and Skoog (MS) medium with or without CoCl2 supplementation. Methylobacterium sp. strain P1-11 produced detectable amounts of vitamin B12 in planta: 1.654 and 2.559 μg per g of dry weight without and with CoCl2 supplementation, respectively.

CONCLUSION

This is the first time a bacterial endophyte was used to produce vitamin B12 in planta, suggesting that bacterial endophytes could be utilized to enhance the nutraceutical values of plant-based foods. © 2025 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Joint and individual associations between multiple vitamins and sperm quality in adult men

Background

Several studies have suggested that a healthy diet is associated with improved male fertility outcomes. However, the joint and individual associations between the status of multiple vitamins and sperm quality remain unclear.

Objectives

This study aimed to investigate the associations between serum vitamin levels and sperm quality parameters in adult men.

Methods

A cross-sectional study was conducted among 156 adult men seeking fertility care at a reproductive center from December 2023 to June 2024. Blood and semen were collected on the same day to determine the concentrations of nine kinds of vitamins (B1, B2, B6, B9, B12, C, A, D, E) and five parameters of sperm quality [total sperm number, sperm concentration, progressive motile sperm, morphologically normal rate, and DNA fragment index (DFI)]. The joint and individual associations between vitamin levels and sperm quality were analyzed using multiple linear regression and Bayesian kernel machine regression (BKMR) models.

Results

Increased tertiles of vitamin B1 and 1,25-dihydroxyvitamin D3 [1,25-(OH)2-D3] in serum were associated with higher sperm quality (all P for trends < 0.10). Compared with the lowest tertiles, the highest tertiles of vitamin B12 had β: 3.0 (95% CI: 0.8, 5.2) increasing in DFI, and vitamin A was negatively associated with progressive sperm motility (P for trends = 0.05). We generally found null results between multiple vitamin levels and the parameters of sperm quality in the BKMR models.

Discussion

These research findings imply that vitamins could have a dose-dependent dual effect on sperm quality. More specifically, the impact of vitamins varies according to their dosage levels and types. Personalized vitamin supplementation may be more effective than taking multivitamins in improving sperm quality.

Desensitization for Vitamin B12 Hypersensitivity and How to Do It

Vitamin B12 is the common name for a group of cobalamins, which are cobalt corrines. Cobalamins are water-soluble B vitamins. Vitamin B12, as a coenzyme of various enzymes, is an essential component of many key metabolic processes in the body. Vitamin B12 deficiency causes dysfunction of various organs and systems in the body, including the central nervous system. Humans, like other animals, are unable to synthesize cobalamin. This vitamin must be supplied with a balanced diet. The only valuable dietary sources of cobalamin are foods of animal origin, especially offal (e.g., liver). Vegan and vegetarian diets are deficient in vitamin B12. People who follow this nutritional model require systematic cobalamin supplementation, usually in oral form. Other causes of cobalamin deficiency are various pathogenetic processes, in the course of which any of the stages of the complicated process of absorption of this vitamin from the gastrointestinal tract are impaired. Disorders of intestinal absorption of vitamin B12 require systematic supplementation of cobalamin parenterally (usually by intramuscular or subcutaneous injections) for the rest of life. Supplementary therapy with vitamin B12 may cause various adverse reactions, among which hypersensitivity reactions of various spectrums and intensity of symptoms are possible. According to available data, hypersensitivity to cobalamin is more likely after intramuscular or subcutaneous administration than in oral form. It also seems that long-term administration of cobalamin predisposes to allergy to vitamin B12, regardless of its chemical form. Although hypersensitivity to cobalamin is rather rare, it can also be of great clinical importance. This is due to the fact that vitamin B12 deficiency affects a significant part of the population, especially the elderly and those with chronic diseases that impair its absorption. In addition, supplementary therapy with cobalamin is long-term (usually lifelong) and there is no alternative form of treatment. For these reasons, solutions are sought that will allow for the safe continuation of treatment supplementing cobalamin deficiency. Various cyanocobalamin desensitization protocols are proposed, differing in duration, the dynamics of gradual dose increase, or the method of injection (intramuscular or subcutaneous). An analysis of available data in this field suggests that desensitization with cyanocobalamin seems to be an effective way to obtain tolerance to vitamin B12, allowing for long-term supplementation of this vitamin regardless of the chemical form, dose size, frequency, or route of administration.

Biological, dietetic and pharmacological properties of vitamin B9

Humans must obtain vitamin B9 (folate) from plant-based diet. The sources as well as the effect of food processing are discussed in detail. Industrial production, fortification and biofortification, kinetics, and physiological role in humans are described. As folate deficiency leads to several pathological states, current opinions toward prevention through fortification are discussed. Claimed risks of increased folate intake are mentioned as well as analytical ways for measurement of folate.

Fundamental origins of neural tube defects with a basis in genetics and nutrition

Neural tube defects (NTDs) are leading congenital malformations. Its global prevalence is one in 1000 pregnancies and it has high morbidity and mortality. It has multiple risk factors like genetic errors and environmental stressors like maternal malnutrition and in utero exposure to pollutants like chemicals. The genetic program determines neural tube development based on timely expression of many genes involved in developmental signaling pathways like BMP, PCP and SHH. BMP expression defines ectoderm. SOX represses BMP in ectoderm and convertes to the neuroectoderm. Subsequently, PCP molecules define the tissue patterning for convergent-extension, a critical step in neural tube genesis. Further, SHH sets spatial patterning of the neural tube. Nutrients are the essential major environmental input for embryogenesis. But it may also carry risk factors. Malnutrition, especially folate deficiency, during embryogenesis is a major cause for NTDs. Folate is integral in the One Carbon metabolic pathway. Its deficiency and error in the pathway are implicated in NTDs. Folate supplementation alone is insufficient to prevent NTDs. Thus, a comprehensive understanding of the various risk factors is necessary to strategize reduction of NTDs. We review the current knowledge of various risk factors, like genetic, metabolic, nutritional, and drugs causing NTDs and discuss the steps required to identify them in the early embryogenesis to avoid NTDs.

Evaluating the Effect of Epigallocatechin Gallate (EGCG) in Reducing Folate Levels in Reproductive Aged Women by MTHFR and DHFR Genotype in Combination With Letrozole or Clomiphene

Previous epidemiological studies have suggested that green tea catechins, including Epigallocatechin-3-gallate (EGCG), the most abundant polyphenol in green tea, may be associated with reduced serum folate levels. This is of particular interest as women of childbearing age may be consuming EGCG from tea, dietary supplements, or involved in active clinical trials studying EGCG or green tea extract. EGCG was reported to shrink uterine fibroids in preclinical and clinical studies. This observation led to the development of a multicenter NICHD-funded clinical trial to evaluate the safety of EGCG for treating women with fibroids and unexplained infertility (NCT04177693). To answer the question of whether green tea extract standardized to EGCG led to a reduction in folate, 39 women aged ≥ 18 to ≤ 40 years, with/without uterine fibroids, were evaluated. These women were randomized to receive either EGCG, EGCG + clomiphene, or EGCG + letrozole for 30 days. A daily dose of 720 mg of highly characterized green tea extract containing EGCG was used. Participants were genotyped for polymorphisms at positions 677 and 1298 in MTHFR and for the -19 bp deletion polymorphism of DHFR. During the intervention with EGCG, folate levels remained in the normal range in all subjects. Our data suggest that in reproductive-age women, a 30-day course of EGCG 720 mg daily taken alone or in combination with clomiphene citrate or letrozole (for 5 days) is well-tolerated and is not associated with folate deficiency even in the presence of MTHFR and/or DHFR polymorphisms known to negatively impact folate synthesis. Trial Registration: Clinical trial: NCT01311869.

Contribution of haptoglobin phenotypic variation to the presence of hyperhomocysteinemia in type 2 diabetics with and without angiopathy

BACKGROUND/AIM

The genetic polymorphism of haptoglobin (Hp) has been associated with several cardiovascular risk factors, but a possible relationship between Hp phenotypic variation and increased levels of homocysteine (Hcy) and cysteine (Cy) is still unknown. The objective of this study is to evaluate the relationship between the Hp polymorphism and hyperhomocysteinemia (HHcy) and hypercysteinemia (HCy) in type 2 diabetics (T2D) with and without angiopathy (AGP).

METHODS

A case-control study was carried out on 293 adults: Group I (GI) - 75 subjects with T2D and AGP; Group II (GII) - 75 subjects with T2D without AGP; Group III (GIII) - 143 controls. Plasma levels of Hcy, Cy and vitamin B6 were measured by high performance liquid chromatography (HPLC) and vitamins B9 and B12 determined by electrochemiluminescence (ECL). The Hp polymorphism was identified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and peroxidase staining. The results were analyzed in SPSS®, version 26.0 with a significance of 95%.

RESULTS

Mean Hcy concentrations were significantly lower in carriers of the Hp2-2 phenotype (6.14 µM; p = 0.046) compared to the other genotypes. The presence of Hp2-1 is associated with an approximately 3.3 times greater probability of occurrence of HHcy (p = 0.015) and 3.7 times greater probability occurrence of HCy (p = 0.021) in T2D with AGP.

CONCLUSION

The presence of the Hp2-1 phenotype is associated with the predisposition of HHcy and HCy in individuals with T2D and AGP, possibly through a positive heterosis mechanism. Carriers of the Hp2-2 phenotype appear to have a greater activation of the transsulfuration pathway in the Hcy cycle and consequent protection for its accumulation.

Inherited disorders of vitamin metabolism

Vitamins are essential cofactors of various enzyme reactions in amino acid, neurotransmitter, nucleotide and energy metabolism. Over the past decade a number of inborn errors of metabolism have been identified, that affect different steps in vitamin absorption, transport, activation or recycling and repair of active vitamin cofactors. According to the respective cofactor function this may result in acute or chronic multisystem disease or in disorders that selectively affect the nervous system. Most of these disorders are amenable to specific treatment with excellent results, but diagnostic delay can lead to rapid, irreversible damage or even death. Therefore, especially in case of acute and severe neurologic presentations compatible with one of the here discused disorders, a vitamin trial should be considered while awaiting results of biochemical and genetic testing. Diagnosis of these disorders is especially rewarding, as treatment is often per oral, available worldwide and comparably cheap. This article will review current knowledge of the clinical presentation, biomarkers and specific treatment of inborn errors of vitamin metabolism and illustrates why child neurologists should have vitamins in their pockets.

Folate alleviated skin inflammation and fibrosis resulting from impaired homocysteine metabolism

Skin fibrosis, characterized by uncontrolled secretion of extracellular matrix (ECM) proteins such as collagen, can lead to excessive scarring and compromised tissue function. Despite the widespread occurrence of fibrotic diseases, effective therapies are lacking. Recent clinical studies have demonstrated a positive correlation between serum homocysteine (Hcy) levels and the severity of systemic sclerosis. However, it remains unclear whether Hcy accumulation plays a pathogenic role in skin fibrosis. Here, we report that Hcy metabolism in fibroblasts plays a crucial role in regulating the pathogenesis of skin fibrosis. Fibrotic skin fibroblasts exhibited elevated levels of Hcy due to the downregulation of catabolism genes CBS and MTR. Experimental skin fibrosis was induced and exacerbated in mouse skin fibroblasts and tissues through adenoviral knockdown of Cbs or Mtr, whereas overexpression of these catabolic genes mitigated the pathogenesis. Furthermore, exogenous Hcy supplementation induced and aggravated the expression of inflammatory and fibrotic genes, promoting both spontaneous and BLM-induced skin fibrosis. Notably, folate administration enhanced Hcy catabolism and ameliorated skin inflammation and fibrosis by inhibiting JAK2/STAT3 signaling pathway. Collectively, these results indicate that skin fibrosis is associated with Hcy metabolic disorders and suggest that targeting Hcy metabolism or supplementing folate may provide a novel strategy for skin fibrosis.

Valeriana jatamansi jones improves depressive behavior in CUMS mice by modulating vitamin B12-related ileal homeostasis

ETHNOPHARMACOLOGICAL RELEVANCE

Valeriana jatamansi Jones (V. jatamansi) is a traditional Chinese medicine (TCM). It was recorded in Diannan Bencao, Compendium of Materia Medica and some local medical books and was described as useful in treating insomnia, distraction, poor mental health, vomiting and diarrhea.

AIM OF THE STUDY

To investigate whether the antidepressant effect of V. jatamansi may operate through modulating vitamin B12-related ileal homeostasis using a chronic unpredictable mild stress (CUMS) mouse model.

MATERIALS AND METHODS

A CUMS-induced depression model was established in mice for five weeks, after which V. jatamansi extracts were administered for three weeks. At week eight, the forced swimming test and novelty-suppressed feeding test were conducted. H&E staining assessed ileal pathology, while 16S rDNA sequencing analyzed changes in ileal microbiota. Additionally, B12 in serum, cubilin (CUBN) and amnionless (AMN) in ileal tissue, methionine synthase (MS) and homocysteine (Hcy) in the hippocampus were measured using ELISA, and the correlations between them and ileal microbiota were explored.

RESULTS

Mice in the model group exhibited significant depressive behavior. However, after treatment with V. jatamansi, immobility time and feeding latency were improved. H&E staining demonstrated the repairing effect of V. jatamansi on the ileum regarding tissue damage. The alpha and beta diversity of the ileal microbiota were regulated and converged to the normal group. Additionally, V. jatamansi modulated B12, CUBN, AMN, MS, and Hcy levels. Correlation analysis showed that there are certain correlations between a variety of microorganisms and B12-related factors.

CONCLUSION

These findings suggest that the mechanism of V. jatamansi in treating depression may be through repairing depression-associated intestinal damage. This repair process may affect the intestinal absorption and microbial production of B12. By reversing the reduction of serum B12, V. jatamansi ultimately reduces the infiltration of Hcy into the CNS.

Recent Advances on the Role of B Vitamins in Cancer Prevention and Progression

Water-soluble B vitamins, mainly obtained through dietary intake of fruits, vegetables, grains, and dairy products, act as co-factors in various biochemical processes, including DNA synthesis, repair, methylation, and energy metabolism. These vitamins include B1 (Thiamine), B2 (Riboflavin), B3 (Niacin), B5 (Pantothenic Acid), B6 (Pyridoxine), B7 (Biotin), B9 (Folate), and B12 (Cobalamin). Recent studies have shown that besides their fundamental physiological roles, B vitamins influence oncogenic metabolic pathways, including glycolysis (Warburg effect), mitochondrial function, and nucleotide biosynthesis. Although deficiencies in these vitamins are associated with several complications, emerging evidence suggests that excessive intake of specific B vitamins may also contribute to cancer progression and interfere with therapy due to impaired metabolic and genetic functions. This review discusses the tumor-suppressive and tumor-progressive roles of B vitamins in cancer. It also explores the recent evidence on a comprehensive understanding of the relationship between B vitamin metabolism and cancer progression and underscores the need for further research to determine the optimal balance of B vitamin intake for cancer prevention and therapy.

Neurotoxicity mechanisms and clinical implications of six common recreational drugs

The recreational abuse of addictive drugs poses considerable challenges to public health, leading to widespread neurotoxicity and neurological dysfunction. This review comprehensively examines the neurotoxic mechanisms, clinical manifestations, and treatment strategies associated with six commonly abused substances: methamphetamine, cocaine, synthetic cathinones, ketamine, nitrous oxide and heroin. Despite their diverse pharmacological properties, these drugs converge on shared neurotoxic pathways, including oxidative stress, mitochondrial dysfunction, excitotoxicity, and neuroinflammation. Psychostimulants, such as methamphetamine, cocaine and synthetic cathinones, disrupt monoaminergic neurotransmission, causing cognitive impairment, psychiatric disturbances, and neurovascular damage. Dissociative anesthetics, including ketamine and nitrous oxide, impair glutamatergic transmission and mitochondrial function, thereby exacerbating excitotoxicity and neuronal apoptosis. Opioids, such as heroin, primarily target the brain's reward system and induce oxidative stress, neuroinflammation, and cerebrovascular complications. Treatment strategies remain limited, focusing on symptomatic management, neuroprotective interventions, and behavioral therapies. Emerging approaches, such as antioxidants, NMDA receptor modulators, and cognitive rehabilitation, show promise but require further validation. By highlighting the underlying mechanisms and therapeutic challenges, this review provides a foundation for developing targeted interventions and advancing research on drug-induced neurotoxicity.

Influence of feeding time on daily rhythms of locomotor activity, clock genes, and epigenetic mechanisms in the liver and hypothalamus of the European sea bass (Dicentrarchus labrax)

The circadian system plays a crucial role in most physiological processes. The molecular clock is linked to epigenetic mechanisms, both of which are influenced by nutrient status and, consequently, to feeding. This research investigated how feeding times (mid-light, ML, vs. mid-dark, MD) synchronize daily rhythms of behavior, clock genes, and epigenetic mechanisms in the European sea bass (Dicentrarchus labrax), focusing on hypothalamus and liver to assess the impact on central and peripheral pacemakers. Feeding at MD influenced the molecular clock of the hypothalamus, causing shifts in acrophases (peaks) for genes of the negative loop (per1b, per2, cry1a). In the liver, the ML fed group showed rhythmic expression for all clock genes, whereas only per2 maintained the rhythms in the MD group. Epigenetic genes related to methylation (dnmt1, dnmt3a) and demethylation (tet2, gadd45aa, mbd4) in the liver displayed rhythmic expression in the ML group, but only dnmt3a maintained the rhythm in the MD group. Nutrient-related factors (SAM and SAH) showed differences between day and night, suggesting a different utilization based on feeding times. Finally, sirt1, a gene involved in deacetylation, displayed a clear daily rhythm in the ML group. All epigenetic genes peaked during the night (resting phase). Overall, these findings indicated feeding time serves as a potent zeitgeber, synchronizing circadian clock and epigenetic rhythms in the liver, with peaks during the resting phase, suggesting this phase represents the adequate time for epigenetic modifications.

Novel Method for the Synthesis of Hydroxycobalamin[c-lactam] and Its Impact on Melanoma Cells In Vitro

The ability to over-proliferate is a hallmark of cancer cells, so inhibiting proliferation is crucial for successful cancer treatment. Vitamin B12 (cobalamin) is among the factors necessary for replication of genetic material and cell division. There is currently no cobalamin antagonist with therapeutic use. Nevertheless, the idea of inhibiting cobalamin-dependent metabolic pathways as a potential anticancer strategy is of interest to many researchers. In this study, we investigated, for the first time, the impact of cobalamin deficiency on melanoma cells' growth. To achieve a cobalamin-deficient state in cellulo, hydroxycobalamin[c-lactam] was used as an antivitamin B12. Here, we describe a new and efficient method for synthesizing this analog from hydroxycobalamin. Interestingly, no cytostatic effect of cobalamin deficiency was observed on C32 and COLO 829 melanoma cell lines. However, we show the variously enhanced pro-proliferative action of vitamin B12 towards these cells. The presented experimental model can be used for further studies on the effects of the cobalamin status on melanoma cells.

Vitamin B12, folate, and homocysteine levels in children and adolescents with obesity: a systematic review and meta-analysis

Background and aims

Childhood and adolescent obesity is a global public health concern. Obesity induces several metabolic disturbances. Several studies have explored the association of vitamin B12, folate, and homocysteine (Hcy) with obesity. This study aimed to synthesize the available evidence regarding the differences in serum levels of vitamin B12, Hcy, and folate among children or adolescents with and without obesity.

Methods

A random-effects meta-analysis using the Sidik-Jonkman method and corrected 95% confidence interval (CI) using the truncated Knapp-Hartung standard errors was used for all meta-analyses. Standardized mean difference (SMD) with the corresponding 95% CI was used as the only effect size. The Cochran's Q test and the I2 statistic were used to evaluate between-study heterogeneity. Publication bias was assessed using funnel plots and the Egger test.

Results

Twenty studies were included with a combined study population of 7,791 patients. There were no significant differences between children/adolescents with and without obesity with respect to serum vitamin B12 levels (SMD: -0.24; 95% CI: -0.53 to 0.06; p > 0.05, I2 = 74.93%) and folate levels (SMD: -0.12; 95% CI: -0.29 to 0.06; p > 0.05, I2 = 19.6%). However, children/adolescents with obesity had significantly higher Hcy levels compared to counterparts without obesity (SMD: 0.77; 95% CI: 0.39 to 1.14; p < 0.001, I2 = 86.4%).

Conclusion

Children and adolescents with obesity had higher Hcy levels than those without obesity. However, no significant differences were found for vitamin B12 and folate levels. Hcy may play a role in the development of obesity in this population.

Metabolism of inorganic arsenic in mice carrying the human AS3MT gene and fed folate deficient or folate supplemented diet

Arsenic (+3 oxidation state) methyltransferase (AS3MT) catalyzes the S-adenosylmethionine (SAM)-dependent methylation of inorganic arsenic (iAs), yielding monomethyl‑arsenic (MAs) and dimethyl‑arsenic (DMAs) metabolites. The formation of DMAs in this pathway is considered a key mechanism for iAs detoxification. Availability of SAM for iAs methylation depends in part on dietary intake of folate. Results of population studies suggest that supplementation with folate stimulates iAs methylation, increasing DMAs and decreasing iAs and MAs proportions in urine and/or blood. The goal of the present study was to determine if folate intake affects methylation and clearance of iAs in a recently established mouse strain that expresses human AS3MT and exhibits a human-like pattern of iAs metabolism. The humanized male and female mice were fed folate-deficient (FD) or folate-supplemented (FS) diet for 6 weeks, followed by exposure to 0 ppb or 400 ppb iAs in drinking water for 5 weeks, while on the same types of diet. The concentrations and proportions of iAs, MAs and DMAs were determined in urine, liver, kidneys, and spleen. The diet-, sex- and dose-related differences were assessed by t-test or a non-parametric test; Bonferroni test was used to correct for multiple comparisons. In general, proportions of DMAs were greater and proportions of iAs were smaller in urine and tissues of FS mice as compared to FD mice. However, folate supplementation also increased MAs proportions. Notably, the folate intake had no effect on the concentrations of total arsenic either in the urine or the tissues. These results suggest that, similar to humans, folate supplementation stimulates iAs methylation in the humanized mice. However, the stimulation of iAs methylation is not associated with clearance of arsenic from tissues, possibly due to an inefficient conversion of MAs to DMAs.

Vitamin Bs as Potent Anticancer Agents through MMP-2/9 Regulation

In recent years, the role of coenzymes, particularly those from the vitamin B group in modulating the activity of metalloenzymes has garnered significant attention in cancer treatment strategies. Metalloenzymes play pivotal roles in various cellular processes, including DNA repair, cell signaling, and metabolism, making them promising targets for cancer therapy. This review explores the complex interplay between coenzymes, specifically vitamin Bs, and metalloenzymes in cancer pathogenesis and treatment. Vitamins are an indispensable part of daily life, essential for optimal health and well-being. Beyond their recognized roles as essential nutrients, vitamins have increasingly garnered attention for their multifaceted functions within the machinery of cellular processes. In particular, vitamin Bs have emerged as a pivotal regulator within this intricate network, exerting profound effects on the functionality of metalloenzymes. Their ability to modulate metalloenzymes involved in crucial cellular pathways implicated in cancer progression presents a compelling avenue for therapeutic intervention. Key findings indicate that vitamin Bs can influence the activity and expression of metalloenzymes, thereby affecting processes such as DNA repair and cell signaling, which are critical in cancer development and progression. Understanding the mechanisms by which these coenzymes regulate metalloenzymes holds great promise for developing novel anticancer strategies. This review summarizes current knowledge on the interactions between vitamin Bs and metalloenzymes, highlighting their potential as anticancer agents and paving the way for innovative, cell-targeted cancer treatments.

Homocysteine Metabolites, Endothelial Dysfunction, and Cardiovascular Disease

Atherosclerosis is accompanied by inflammation that underlies cardiovascular disease (CVD) and its vascular manifestations, including acute stroke, myocardial infarction, and peripheral artery disease, the leading causes of morbidity/mortality worldwide. The monolayer of endothelial cells formed on the luminal surface of arteries and veins regulates vascular tone and permeability, which supports vascular homeostasis. Endothelial dysfunction, the first step in the development of atherosclerosis, is caused by mechanical and biochemical factors that disrupt vascular homeostasis and induce inflammation. Together with increased plasma levels of low-density lipoprotein (LDL), diabetes, hypertension, cigarette smoking, infectious microorganisms, and genetic factors, epidemiological studies established that dysregulated metabolism of homocysteine (Hcy) causing hyperhomocysteinemia (HHcy) is associated with CVD. Patients with severe HHcy exhibit severe CVD and die prematurely due to vascular complications. Biochemically, HHcy is characterized by elevated levels of Hcy and related metabolites such as Hcy-thiolactone and N-Hcy-protein, seen in genetic and nutritional deficiencies in Hcy metabolism in humans and animals. The only known source of Hcy in humans is methionine released in the gut from dietary protein. Hcy is generated from S-adenosylhomocysteine (AdoHcy) and metabolized to cystathionine by cystathionine β-synthase (CBS) and to Hcy-thiolactone by methionyl-tRNA synthetase. Hcy-thiolactone, a chemically reactive thioester, modifies protein lysine residues, generating N-homocysteinylated (N-Hcy)-protein. N-Hcy-proteins lose their normal native function and become cytotoxic, autoimmunogenic, proinflammatory, prothrombotic, and proatherogenic. Accumulating evidence, discussed in this review, shows that these Hcy metabolites can promote endothelial dysfunction, CVD, and stroke in humans by inducing pro-atherogenic changes in gene expression, upregulating mTOR signaling, and inhibiting autophagy through epigenetic mechanisms involving specific microRNAs, histone demethylase PHF8, and methylated histone H4K20me1. Clinical studies, also discussed in this review, show that cystathionine and Hcy-thiolactone are associated with myocardial infarction and ischemic stroke by influencing blood clotting. These findings contribute to our understanding of the complex mechanisms underlying endothelial dysfunction, atherosclerosis, CVD, and stroke and identify potential targets for therapeutic intervention.

Vitamin B12: prevention of human beings from lethal diseases and its food application

Vitamin B12, a water-soluble essential micronutrient, plays a pivotal role in numerous physiological processes in the human body. This review meticulously examines the structural complexity and the diverse mechanisms through which vitamin B12 exerts its preventive effects against a spectrum of health conditions, including pernicious anaemia, neurological disorders, obesity, diabetes, dyslipidaemia and complications in foetal development. The selection of articles for this review was conducted through a systematic search across multiple scientific databases, including PubMed, Scopus and Web of Science. Criteria for inclusion encompassed relevance to the biochemical impact of vitamin B12 on health, peer-reviewed status and publication within the last decade. Exclusion criteria were non-English articles and studies lacking empirical evidence. This stringent selection process ensured a comprehensive analysis of vitamin B12's multifaceted impact on health, covering its structure, bioavailable forms and mechanisms of action. Clinical studies highlighting its therapeutic potential, applications in food fortification and other utilizations are also discussed, underscoring the nutrient's versatility. This synthesis aims to provide a clear understanding of the integral role of vitamin B12 in maintaining human health and its potential in clinical and nutritional applications. © 2024 The Author(s). Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

The effects of age and sex on reference intervals for cobalamin, homocysteine, and serum and urinary methylmalonic acid in healthy adult dogs

BACKGROUND

In dogs, data on reference intervals (RIs) for cobalamin, markers of metabolism (markersB12met), age and sex effects are limited.

HYPOTHESIS/OBJECTIVES

Establish RI for serum cobalamin, homocysteine, and methylmalonic acid (sMMA) concentrations, urinary methylmalonic acid-to-creatinine ratio (uMMA:crea), and determine effects of sex and age.

METHODS

Prospective study using healthy dogs (1-10 years). Cobalamin and markersB12met were determined using chemiluminescence immunoassay (cobalamin) and liquid chromatography/tandem mass spectrometry (homocysteine, sMMA, uMMA:crea). In dogs with outlying data, changes in health, markersB12met, and onset of gastrointestinal signs were reevaluated after 9-15 months.

RESULTS

Twelve of 120 healthy dogs had abnormal uMMA:crea ratios. No other cobalamin analyte outliers were found. Outlying data re-examination (odRE) was performed in 10/12 dogs. Chronic gastrointestinal signs occurred in 64% of odRE-dogs, whereas 36% remained healthy. In total, 112 dogs (67 females, 45 males; median ages, 3.5 and 3.75 years, respectively) were included in RI analyses. Reference intervals were 178.5-851 pmol/L (cobalamin), 5.8-29.0 μmol/L (homocysteine), 45.3-159.5 μg/L (sMMA), and ≤22.4 mg/g (uMMA:crea). Only age affected cobalamin concentrations (significant decrease). Compared by sex and neuter status, intact male dogs had significantly higher uMMA:crea ratios (median, 13.5; range, 1.9-83.6 mg/g) than the other groups (median, 2.5; range, 0.7-9.7 mg/g; P < .0001). Sex-specific RI were ≤58.9 mg/g (intact male) vs ≤5.2 mg/g (females and neutered males).

CONCLUSION AND CLINICAL IMPORTANCE

Intact male dogs had significantly higher uMMA:crea ratios than the other groups. Thus, sex-specific RI are recommended for uMMA:crea. Because of the wide distribution of uMMA:crea ratios, careful interpretation in intact male dogs is advised.

Possible Metabolic Remodeling based on de novo Biosynthesis of L-serine in Se-Subtoxic or -Deficient Mammals

Current research studies point to an increased risk of diabetes with selenium (Se) intake beyond the physiological requirement used to prevent cancers. The existing hypothesis of "selenoprotein overexpression leads to intracellular redox imbalance" cannot clearly explain the U-shaped dose-effect relationship between Se intake and the risk of diabetes. In this review, it is speculated that metabolic remodeling based on the de novo biosynthesis of L-serine may occur in mammals at supranutritional or subtoxic levels of Se. It is also speculated that a large amount of L-serine is consumed by the body during insufficient Se intake, thus resulting in similar metabolic reprogramming. The increase in atypical ceramide and its derivatives due to the lack of L-serine may also play a role in the development of diabetes.

S-adenosylmethionine and S-adenosyl-L-homocysteine metabolism is involved in the sperm motility and in vitro fertility rate in mouse

Increased fragmentation of sperm DNA has been implicated in male infertility. Folate deficiency results in impaired methionine synthesis, depletion of S-adenosylmethionine (SAM) levels, an increase in S-adenosyl-l-homocysteine (SAH) levels, and increased DNA fragmentation. Disruption of the dynamic balance between SAM and SAH may also contribute, although the details of this process are not yet fully understood. We investigated the localization of SAM, SAH, and S-adenosylhomocysteine hydrolase (SAHH), and whether SAM/SAH metabolism contributes to sperm motility and fertilization rate. SAM, SAH, and SAHH levels were assessed in the acrosome, midpiece, and tail of spermatozoa. Chemical inhibition of SAM/SAH metabolism and extracellular SAH significantly decreased the straight-line velocity (VSL), curvilinear velocity (VCL), and amplitude lateral head displacement (ALH) of sperm cells, which were thus unable to swim forward and perform oscillatory movements in place. This significantly reduced the fertilization rate. Therefore, the disruption of the SAM/SAH balance may contribute to male infertility.

International Symposium on Ruminant Physiology: One-carbon metabolism in beef cattle throughout the production cycle

One-carbon metabolism (OCM) is a series of connected pathways involving the methionine-folate cycles, transsulfuration, polyamine synthesis, nucleotide synthesis, free-radical scavenging, and energy metabolism. These pathways functionally depend upon amino acids (methionine, glycine, and serine), vitamins (folate, B2, B6, and B12), and minerals (sulfur, cobalt, and zinc). Growing bodies of research indicate that in beef cattle, physiological stage, nutritional plane, diet, species (Bos taurus vs. indicus), rumen protected vs. not, individual vs. combination supplementation and method of delivery all affect the efficacy of one-carbon metabolite supplementation. Infusion studies showed that supplementing methionine to growing steers improved N retention and altered hepatic activity of methionine synthase; however, only supplementing methionine without folate decreased folate concentrations in circulation. When heifers were supplemented with methionine, choline, folate, and B12 for the first 63 d of gestation, metabolomic analysis revealed increasing OCM analytes to the heifer, but a buffering effect to the fetus with minimal changes seen in hepatic metabolite abundance. Methionine supplementation to heifers during the periconceptual period increased circulating methionine but shifted fetal hepatic metabolism toward the transsulfuration pathway. Periconceptual methionine supplementation to cows increased gain and total-tract digestibility in calves post-weaning. In vitro supplementation of choline to beef cattle embryos results in calves of increased birth and weaning weight. Overall, these data demonstrate that OCM is altered in those cattle receiving one-carbon metabolites, and that a metabolic programming response is elicited in offspring receiving supplements in vitro or during early gestation. Research should be considered to maximize efficiency of beef cattle production at all stages by identifying limiting metabolites or enzymes to maximize efficiency of OCM in beef cattle, as well as to understand the concerted effects of multiple one-carbon metabolites to balance the stoichiometry of the pathway.

The association between serum folate and elderly diastolic hypertension: results from the NHANES (2007-2018)

AIM

To explore the association between serum folate concentration and the prevalence of elderly diastolic hypertension. This study aims to identify potential relationships that could inform further research into the mechanisms underlying hypertension management.

METHODS

Data from six NHANES cycles (2007-2008, 2009-2010, 2011-2012, 2013-2014, 2015-2016, and 2017-2018) were analysed for individuals aged over 60. Weighted logistic regression estimated odds ratios (ORs) and 95% confidence intervals (CIs). Subgroup and restricted cubic spline (RCS) regression explored the serum folate concentration and elderly diastolic hypertension relationship.

RESULTS

This study included 9,419 participants (4,734 females and 4,685 males) with a mean age of 70.0 ± 7.0 years. Among them, 360 were diagnosed with diastolic hypertension. In the fully adjusted model, there was a negative correlation between serum folate concentration and the prevalence of diastolic hypertension (OR 0.65; 95% CI: 0.52-0.82). When serum folate concentration levels were divided into quartiles (in μg/dL), the ORs for diastolic hypertension corresponding to Q2 (1.29-1.98), Q3 (1.99-3.08), and Q4 (3.09-5.56) levels compared to Q1 (0.18-1.28) were 1.41 (95% CI: 0.60-3.33), 0.48(95% CI: 0.20-1.16), and 0.35 (95% CI: 0.16-0.74), respectively, with a P for trend <.05. Restricted cubic spline plots showed a negative correlation between serum folate concentration and the prevalence of diastolic hypertension (non-linearity: p = .495). Subgroup analysis indicated that the negative correlation between serum folate concentration and the prevalence of diastolic hypertension was more significant in female participants (interaction p = .009).

CONCLUSION

Higher serum folate concentration is associated with a lower prevalence of diastolic hypertension in the elderly.

Clinical, biochemical, molecular characteristics and clinical outcome of hyperhomocysteinemia in Malaysian children

BACKGROUND

Hyperhomocysteinemia can be due to various abnormalities of the complex interaction of methionine, folate and vitamin B12. It has been known to be a cardiovascular risk factor. This study aims to review the clinical presentation, underlying causes and clinical outcome in paediatric patients diagnosed with significant hyperhomocysteinemia in Malaysia.

DESIGN AND METHODS

Data were obtained from the medical records and the laboratory information system. Paediatric patients with significant hyperhomocysteinemia were identified from a selective high-risk screening of 96,721 patients, performed between 2010 and 2022. Inclusion criteria for the study were paediatric patients with significant hyperhomocysteinemia (>40 µmol/L).

RESULTS

Sixteen patients were identified. The average total homocysteine (tHcy) and methionine were 269 µmol/L and 499 µmol/L in cystathionine β-synthase deficiency (CBS), 127 µmol/L and 29 µmol/L in patients with remethylation defects and 390 µmol/L and 4 µmol/L in congenital B12 deficiency. We found c.609G>A as the most prevalent mutation in MMACHC gene and possible novel mutations for CBS (c.402del, c.1333C>T and c.1031T>G) and MTHFR genes (c.266T>A and c.1249del). Further subclassification revealed CBS was 5/16 patients (31 %), remethylation defects was 9/16 (56 %) and congenital B12 deficiency was 2/16 (13 %). All patients received standard treatment and regular monitoring of the main biomarkers. The average age at the time of diagnosis were 9.2 years (CBS) and 1.2 years (remethylation defects). Congenital B12 deficiency had slight delay in milestones, remethylation defects had mild to moderate learning disabilities, CBS had variable degree of intellectual disability, delayed milestones, ophthalmological abnormalities, and thrombosis at an early adolescent/adulthood.

CONCLUSIONS

The majority of significant hyperhomocysteinemia in Malaysian children was due to remethylation defects. Screening for hyperhomocysteinemia in Malaysian children is recommended for earlier treatment and improved clinical outcome.

Expression patterns of folate metabolism-related enzymes in the bovine oviduct: estrous cycle-dependent modulation and responsiveness to folic acid

Folate metabolism is required for important biochemical processes that regulate cell functioning, but its role in female reproductive physiology in cattle during peri- and post-conceptional periods has not been thoroughly explored. Previous studies have shown the presence of folate in bovine oviductal fluid, as well as finely regulated gene expression of folate receptors and transporters in bovine oviduct epithelial cells (BOECs). Additionally, extracellular folic acid (FA) affects the transcriptional levels of genes important for the functioning of BOECs. However, it remains unknown whether the anatomical and cyclic features inherent to the oviduct affect regulation of folate metabolism. The present study aimed to characterize the gene expression pattern of folate cycle enzymes in BOECs from different anatomical regions during the estrous cycle and to determine the transcriptional response of these genes to increasing concentrations of exogenous FA. A first PCR screening showed the presence of transcripts encoding dihydrofolate reductase (DHFR), methylenetetrahydrofolate reductase (MTHFR), and methionine synthase (MTR) in bovine reproductive tissues (ovary, oviduct and uterus), with expression levels in oviductal tissues comparable to, or even higher than, those detected in ovarian and uterine tissues. Moreover, expression analysis through RT-qPCR in BOECs from the ampulla and isthmus during different stages of the estrous cycle demonstrated that folate metabolism-related enzymes exhibited cycle-dependent variations. In both anatomical regions, DHFR was upregulated during the preovulatory stage, while MTHFR and MTR exhibited increased expression levels during the postovulatory stage. Under in vitro culture conditions, ampullary and isthmic cells were cultured in the presence of 10, 50, and 100 μM FA for 24 h. Under these conditions, isthmus epithelial cells exhibited a unique transcriptional response to exogenous FA, showing a pronounced increase in MTR expression levels. Our results suggest that the expression of folate metabolism-related genes in BOECs is differentially regulated during the estrous cycle and may respond to exogenous levels of folate. This offers a new perspective on the transcriptional regulation of genes associated with the folate cycle in oviductal cells and provides groundwork for future studies on their functional and epigenetic implications within the oviductal microenvironment.

Nitrous oxide abuse direct measurement for diagnosis and follow-up: update on kinetics and impact on metabolic pathways

Recreational use of nitrous oxide (N2O) has become a major health issue worldwide, with a high number of clinical events, especially in neurology and cardiology. It is essential to be able to detect and monitor N2O abuse to provide effective care and follow-up to these patients. Current recommendations for detecting N2O in cases of recreational misuse and consumption markers are lacking. We aimed to update current knowledge through a review of the literature on N2O measurement and kinetics. We reviewed the outcomes of experiments, whether in preclinical models (in vitro or in vivo), or in humans, with the aim to identify biomarkers of intoxication as well as biomarkers of clinical severity, for laboratory use. Because N2O is eliminated 5 min after inhalation, measuring it in exhaled air is of no value. Many studies have found that urine and blood matrices concentrations are connected to ambient concentrations, but there is no similar data for direct exposure. There have been no studies on N2O measurement in direct consumers. Currently, patients actively abusing N2O are monitored using effect biomarkers (biomarkers related to the effects of N2O on metabolism), such as vitamin B12, homocysteine and methylmalonic acid.

Presence of vitamin B12 metabolism in the last common ancestor of land plants

Vitamin B12, also known as cobalamin, is an essential organic cofactor for methionine synthase (METH), and is only synthesized by a subset of bacteria. Plants and fungi have an alternative methionine synthase (METE) that does not need B12 and are typically considered not to utilize it. Some algae facultatively utilize B12 because they encode both METE and METH, while other algae are dependent on B12 as they encode METH only. We performed phylogenomic analyses of METE, METH and 11 further proteins involved in B12 metabolism across more than 1600 plant and algal genomes and transcriptomes (e.g. from OneKp), demonstrating the presence of B12-associated metabolism deep into the streptophytes. METH and five further accessory proteins (MTRR, CblB, CblC, CblD and CblJ) were detected in the hornworts (Anthocerotophyta), and two (CblB and CblJ) were identified in liverworts (Marchantiophyta) in the bryophytes, suggesting a retention of B12-metabolism in the last common land plant ancestor. Our data further show more limited distributions for other B12-related proteins (MCM and RNR-II) and B12 dependency in several algal orders. Finally, considering the collection sites of algae that have lost B12 metabolism, we propose freshwater-to-land transitions and symbiotic associations to have been constraining factors for B12 availability in early plant evolution. This article is part of the theme issue 'The evolution of plant metabolism'.

Comparative bioavailability study of supplemental oral Sucrosomial vs. oral conventional vitamin B12 in enhancing circulatory B12 levels in healthy deficient adults: a multicentre, double-blind randomized clinical trial

Background

Vitamin B12 is essential for neurological function, red blood cell formation, and DNA synthesis. Deficiency can lead to diverse health conditions, including megaloblastic anemia and neurological issues. Oral supplementation is a standard treatment for B12 deficiency. The Sucrosomial® carrier system offers an innovative approach that enhances supplemental nutrient absorption and bioavailability.

Objectives

This study aimed to compare the effectiveness of oral Sucrosomial® vitamin B12 formulation vs various conventional B12 supplements, randomly selected from local pharmacies, in increasing and maintaining circulatory B12 levels in healthy deficient adults (200-300 pg/mL).

Methods

A randomized, double-blind clinical trial was conducted across three centers in Pakistan from April to July 2024. At KEMU, participants received either Sucrosomial® vitamin B12 or Mecogen SL B12; at LRH, Sucrosomial® B12 or B-SUB B12; and at LUMHS, Sucrosomial® B12, Evermin B12, or Neuromax B12. Participants took a daily single dose of 1,000 μg of the assigned B12 formulation for 7 days. Serum B12 levels were measured at baseline (day 0) and on days 1, 3, 5, and 7.

Results

Sucrosomial® B12 was significantly more effective than conventional B12 formulations in increasing and maintaining higher serum B12 levels across all time points. At KEMU, it reached a peak concentration of 454 ± 3.9 pg/mL by day 5, compared to 274 ± 11.1 pg/mL with Mecogen SL B12. At LRH, it peaked at 496 ± 34.4 pg/mL by day 5 versus 304 ± 49.4 pg/mL for B-SUB B12. At LUMHS, it reached 592.7 ± 74.3 pg/mL by day 7, compared to 407.24 ± 41.6 pg/mL for Evermin B12 and 263.82 ± 23.8 pg/mL for Neuromax B12. Sucrosomial® B12 was the only formulation to surpass the deficiency-borderline threshold (200-300 pg/mL) within 24 h of the first dose and was well tolerated with no reported side effects.

Conclusion

Sucrosomial® vitamin B12 demonstrated superior efficacy in rapidly and consistently elevating and maintaining higher circulatory B12 levels compared to conventional supplements. Its characteristic absorption mode and proven efficacy suggest it could effectively address B12 deficiency in a broad range of populations, including those with gastrointestinal conditions and pernicious anemia, thereby supporting overall health.

Clinical trial registration

clinicaltrials.gov, NCT06376591.

Asymptomatic pediatric presentation of S-adenosylhomocysteine hydrolase deficiency

S-adenosylhomocysteine hydrolase deficiency is an autosomal recessive inborn error of metabolism affecting methylation by disrupting the methionine cycle. Its clinical spectrum spans from severe perinatal encephalomyopathy and liver failure to asymptomatic course in patients with isolated hypermethioninemia. We present two new cases of S-adenosylhomocysteine hydrolase deficiency from Pakistani origin clinically asymptomatic at presentation. Both siblings showed mild chronic liver failure and elevation of creatine kinase. The older patient presented at 6 years of age with isolated verbal processing difficulty and mild diffuse leukodystrophy, reversible 12 months after introduction of methionine dietary restriction. The patient showed subtle atrophy in the muscle MRI at the age of 7 years. S-adenosylhomocysteine hydrolase deficiency was confirmed with homozygous missense variant c.146G>A (p.Arg49His) in the AHCY gene, a genotype previously reported in Pakistani patients with mild presentation. Dietary methionine restriction decreased plasma methionine but not plasma S-adenosylhomocysteine and S-adenosylmethionine. This work expands the mild spectrum of S-adenosylhomocysteine hydrolase deficiency with no noticeable clinical symptoms in children, highlighting a specific hotspot variant from South Asia. This mild form of the disease is likely underdiagnosed and raises the question of therapeutic management to prevent long-term complications documented in the literature, such as hepatocellular carcinoma and myopathy in early adulthood.

Transcriptomics-guided optimization of vitamins to enhance erythromycin yield in saccharopolyspora erythraea

Comparative transcriptomics uncovered distinct expression patterns of genes associated with cofactor and vitamin metabolism in the high-yielding mutant strain Saccharopolyspora erythraea HL3168 E3, as compared to the wild-type NRRL 2338. An in-depth analysis was conducted on the effects of nine vitamins, and it was determined that thiamine pyrophosphate (TPP), vitamin B2, vitamin B6, vitamin B9, vitamin B12, and hemin are key enhancers in erythromycin production in E3, increasing the erythromycin titer by 7.96-12.66%. Then, the Plackett-Burman design and the path of steepest ascent were applied to further optimize the vitamin combination for maximum production efficiency, enhancing the erythromycin titer in shake flasks by 39.2%. Otherwise, targeted metabolomics and metabolic flux analysis illuminated how vitamin supplementation modulates the central carbon metabolism with notable effects on the TCA cycle and methionine synthesis to augment the provision of energy and precursors essential for erythromycin synthesis. This work highlights the capacity for precise vitamin supplementation to refine metabolic pathways, thereby boosting erythromycin production, and provides valuable directions for application on an industrial scale.

MTHFR C677T、MTHFR A1298C、MTRR A66G and MTR A2756G polymorphisms and male infertility risk: a systematic review and meta-analysis

BACKGROUND

Epidemiological studies have reported that polymorphisms of folate-metabolizing genes have a significant impact on male infertility. However, the results of published studies have come to different conclusions.

OBJECTIVE

To determine an association between folate-metabolizing gene polymorphisms and the risk of male infertility.

METHODS

The meta-analysis was conducted according to the PRISMA 2020 statement. The protocol was registered with PROSPERO (CRD42023412251). Studies were searched from PubMed, Google Scholar, Embase, Scopus, and the Cochrane Library up to 24st October2023. Articles that satisfied the inclusion criteria were evaluated for their quality using the Newcastle-Ottawa Scale. Data were extracted from the eligible studies and were analyzed for pooled up odds ratio (OR) with 95% confidence interval (CI). Meta-analysis was conducted using STATA 12.

RESULTS

Forty-six case-control studies were included in the meta-analysis which comprised 20,639 participants. The pooled analysis revealed that the MTHFR C677T polymorphism was significantly associated with male infertility and abnormospermia.Three-fifths of the model showed there was a significant association between the MTR A2756G polymorphism and male infertility. Both MTHFR A1298C and MTRR A66G polymorphisms were not significantly associated with male fertility. Furthermore, subgroup analysis revealed a significant association between the MTHFR C677T polymorphism and male fertility in Asian countries.

CONCLUSION

This meta-analysis suggests that the MTHFR C677T and MTR A2756G polymorphisms may be a potential risk factor for male infertility.

Relationship between emotional eating and nutritional intake in adult women with overweight and obesity: a cross-sectional study

BACKGROUND

Emotional eating (EE) is particularly prevalent in overweight or obese women, who may turn to food as a way to cope with stress, sadness, or anxiety. Limited research has been conducted on the association between EE and nutritional intake. Therefore, present study was designed to explore this association in adult women with overweight and obesity.

METHODS

In this cross-sectional study, the relationship between EE and nutritional intake in 303 overweight and obese women (aged 18-50 years) was examined. The researchers used the validated semi-quantitative Food Frequency Questionnaire (FFQ) to assess participants' nutritional intake and the Dutch Eating Behavior Questionnaire (DEBQ) to evaluate their eating behavior. To determine the association between EE and nutritional intake, we employed the multiple linear regression analysis.

RESULTS

The frequency of high intensity EE was 64.4% among the study participants and the mean total score of EE subscale of DBEQ was 2.32 ± 0.81. The total score of EE was positively associated with the energy intake (β = 0.396, P = 0.007), even after adjusting for age and BMI. In addition, a significant inverse association was found between the score of EE and the daily intake of calcium (β= -0.219, P = 0.026), riboflavin (β= -0.166, P = 0.043), and vitamin B12 (β= -0.271, P = 0.035), independent from energy and age. Also the results showed a significant positive association between the score of EE and the frequency of daily intake of cracker, muffin, cake, cream cake, pastry, candy, ice cream, pickles, melon, hydrogenated vegetable oil, peanut, salted and roasted seeds, and corn-cheese puff snack.

CONCLUSION

This study found that overweight or obese women with higher intensity of EE might have a higher intake of energy and a lower intake of dietary calcium, riboflavin and vitamin B12. Integrating a balanced diet with psychotherapy is suggested to help individuals with EE reducing the urge to eat in response to emotions.

The role of micronutrients and serum metabolites in intervertebral disk degeneration: insights from a Mendelian randomization study and mediation analysis

Background

Intervertebral disk degeneration (IVDD) is a complex degenerative skeletal condition, potentially influenced by micronutrients and serum metabolites in its etiology. However, the exact causal relationship between these factors and IVDD remains ambiguous.

Methods

The research employed a Two-Sample Mendelian Randomization (2SMR) analysis to thoroughly evaluate the causal relationship between 15 micronutrients (consisting of 7 minerals and 8 vitamins) as exposure variables, 1,091 blood metabolites, and 309 metabolite ratios as intermediary factors, and IVDD as the outcome. Additionally, reverse MR analysis and mediation analysis were carried out to validate the reliability of the results and explore the underlying mechanism by which micronutrients influence the risk of IVDD by regulating metabolites.

Results

Among the micronutrients examined, vitamin B12 exhibited a noteworthy negative correlation with the incidence of IVDD (OR: 0.752, 95% [CI]: 0.573-0.987, p = 0.040), indicating a potential reduction in IVDD risk with increased vitamin B12 consumption. Of the 1,091 blood metabolites and 309 metabolite ratios analyzed, 52 metabolites displayed significant associations with IVDD, primarily linked to amino acid, fatty acid, nucleotide, and sphingolipid metabolic pathways. Mediation analysis identified 4-acetaminophen sulfate as a potential mediator in the protective effect of vitamin B12 against IVDD.

Conclusion

This study has shown that vitamin B12 may reduce the risk of IVDD and has identified 52 serum metabolites that are associated with IVDD. Furthermore, it proposes that 4-acetaminophen sulfate could serve as a potential mechanism by which vitamin B12 exerts its inhibitory effects on IVDD.

The origin of methyl group in methanogen-mediated mercury methylation: From the Wolfe cycle

Methylmercury (MeHg) is a bioaccumulating neurotoxin mainly produced by anaerobic microorganisms, with methanogen being one of the important methylators. A critical aspect for understanding the mechanism for microbial mercury (Hg) methylation is the origin of the methyl group. However, the origin of methyl group in methanogen-mediated Hg methylation remains unclear. This study aims to identify the source of methyl group for MeHg synthesis in methanogens. Our study revealed that Hg methylation in Methanospirillum hungatei JF-1 is closely related to methanogenesis process, according to the results of proteomic study and substrate limitation study. Next, we proved that nearly all methyl group in MeHg derives from the Wolfe cycle in this species, rather than the previously demonstrated acetyl-coenzyme A pathway, based on the results of 13C labeling study. We then proposed the Wolfe cycle-dependent Hg methylation mechanism in this species. Further genome analyses and 13C labeling experiments indicated that the involvement of the Wolfe cycle in Hg methylation is probably a universal feature among Hg-methylating methanogens. These findings reveal a unique Hg methylation mechanism in methanogens. Our study broadens the carbon substrates and controlling factors for MeHg synthesis in the environment, which can inform the prediction of MeHg production potential and remediation strategies for MeHg contamination.

Associations between Circulating Biomarkers of One-Carbon Metabolism and Mitochondrial D-Loop Region Methylation Levels

BACKGROUND/OBJECTIVES

One-carbon metabolism is a critical pathway for epigenetic mechanisms. Circulating biomarkers of one-carbon metabolism have been associated with changes in nuclear DNA methylation levels in individuals affected by age-related diseases. More and more studies are showing that even mitochondrial DNA (mtDNA) could be methylated. In particular, methylation of the mitochondrial displacement (D-loop) region modulates the gene expression and replication of mtDNA and, when altered, can contribute to the development of human illnesses. However, no study until now has demonstrated an association between circulating biomarkers of one-carbon metabolism and D-loop methylation levels.

METHODS

In the study presented herein, we searched for associations between circulating one-carbon metabolism biomarkers, including folate, homocysteine, and vitamin B12, and the methylation levels of the D-loop region in DNA obtained from the peripheral blood of 94 elderly voluntary subjects.

RESULTS

We observed a positive correlation between D-loop methylation and vitamin B12 (r = 0.21; p = 0.03), while no significant correlation was observed with folate (r = 0.02; p = 0.80) or homocysteine levels (r = 0.02; p = 0.82). Moreover, D-loop methylation was increased in individuals with high vitamin B12 levels compared to those with normal vitamin B12 levels (p = 0.04).

CONCLUSIONS

This is the first study suggesting an association between vitamin B12 circulating levels and mtDNA methylation in human subjects. Given the potential implications of altered one-carbon metabolism and mitochondrial epigenetics in human diseases, a deeper understanding of their interaction could inspire novel interventions with beneficial effects for human health.

Vitamin B12 status in hospitalised cancer patients: Prevalence and clinical implications of depletion and hypervitaminosis

BACKGROUND & AIMS

The prevalence and clinical significance of vitamin B12 alterations in patients with cancer are poorly understood. We aimed to assess the prevalence and risk factors of vitamin B12 depletion or hypervitaminosis in patients with cancer.

METHODS

We retrospectively included hospitalised patients with cancer in 2017-2022. Plasma B12 levels were stratified as very low (VL, <200 pg/ml), low (L, 200-299 pg/ml), normal (N, 300-812 pg/ml), or high (H, ≥813 pg/ml). We collected demographic and several clinical data (e.g., comorbidities, nutritional status, ECOG-PS, cancer site and stage). Univariate and multivariate analyses for factors associated to the vitamin B12 status were fitted.

RESULTS

788 patients (F/M ratio 1.05, median age 72 years, [25th, 75th percentiles 62, 78 years]) were included. Vitamin B12 was VL in 14.1%, L in 19.4%, N in 49.4%, and H in 17.1% cases. Vitamin B12 distribution increased significantly as function of ECOG-PS levels. Patients with breast cancer were characterized by the highest median B12 value, while colorectal cancer patients by the lowest. Vitamin B12 was also significantly higher in advanced compared to early-stage patients as well as in those who had liver failure. Multivariate analysis showed that the probability of H vs. VL B12 levels was significantly increased in patients with hypoproteinemia, hypo-prealbuminemia, and ECOG-PS≥2, and decreased in those with colorectal and gastric cancer.

CONCLUSION

Vitamin B12 impairment is common in cancer patients. Increased vitamin B12 is associated with an impaired clinical status, while vitamin B12 depletion is more common in early-stage cancer and in elderly patients.

Supplementation with Folic Acid or 5-Methyltetrahydrofolate and Prevention of Neural Tube Defects: An Evidence-Based Narrative Review

Background: Folic acid (FA), which in its chemical form is pteroylglutamic acid, is the fully oxidised, water-soluble, monoglutamic form of vitamin B9. This compound is part of the folate group but with higher bioavailability, and it is found in vitamin supplements and fortified foods and drugs. Folate metabolism is complex and associated with various metabolic pathways, all of which confer protection on the cell and allow its survival. Methods: We conducted a non-systematic search of articles published in English and Spanish including controlled trials, cohort studies, systematic re-views, and meta-analyses were included, as well as key studies in animal models related to pharmacokinetic studies. Search terms encompassed: "folic acid", "folates", "5-metyltetrahydrofolate", "5-MTHF", "neural tube defects", "supplementation", "fortification", AND "homocysteine" Results: A crucial role demonstrated for FA is to help prevent neural tube defects (NTDs). However, more studies are definitely still needed to establish 5-MTHF as a safe and effective therapeutic approach comparable with FA. Moreover, there is a lack of clinical studies that evaluate the efficacy of 5-MTHF supplementation in the prevention of NTDs. The present evidence-based narrative review discusses differences between FA and 5-MTHF in terms of structure, metabolism, bioavailability, clinical efficacy, and safety. Conclusions: Despite the potential value of 5-MTHF as an alternative to FA, clinical studies would be urgently needed to support the efficacy, dosage, timing, and/or safety of its use as a supplement.

Effects of 5-Aminolevulinic Acid Supplementation on Gas Production, Fermentation Characteristics, and Bacterial Community Profiles In Vitro

To investigate the effect of 5-aminolevulinic acid (5-ALA) on in vitro rumen gas production, fermentation characteristics, and bacterial community profiles, five levels of 5-ALA (0, 100, 500, 1000, and 5000 mg/kg DM) were supplemented into a total mixed ration (concentrate/forage = 40:60) as substrate in an in vitro experiment. Results showed that as the supplementation level of 5-ALA increased, asymptotic gas production (b) decreased linearly and quadratically (p < 0.01) while the dry matter degradation rate increased quadratically (p < 0.01). Meanwhile, the propionate concentration of 72 h incubation fluid increased linearly (p = 0.03) and pH value increased linearly and quadratically (p < 0.01), while the concentrations of butyrate, isobutyrate, valerate, isovalerate, and NH3-N and the ratio of acetate/propionate (A/P) decreased linearly and quadratically (p < 0.05). There was no significant difference in any alpha diversity indices of bacterial communities among the various 5-ALA levels (p < 0.05). PCoA and PERMANOVA analysis revealed that the bacterial profiles showed a statistical difference between the treatment 5-ALA at 1000 mg/kg DM and the other levels except for 5000 mg/kg DM (p < 0.05). Taxonomic classification revealed a total of 18 and 173 bacterial taxa at the phylum and genus level with relative abundances higher than 0.01% in at least half of the samples, respectively. LEfse analysis revealed that 19 bacterial taxa were affected by 5-ALA levels. Correlation analysis showed that Actinobacteriota was positively correlated with the gas production parameter b, the ratio of A/P, and the concentration of butyrate, isovalerate, and NH3-N (p < 0.05) and negatively correlated with pH (p < 0.05). WPS-2 exhibited a negative correlation with the gas production parameter b, the ratio of A/P, and the concentration of butyrate, valerate, isobutyrate, isovalerate, and NH3-N (p < 0.05), along with a weaker positive correlation with pH (p = 0.04). The Bacteroidales BS11 gut group was negatively correlated with the concentration of propionate but positively correlated with gas production parameter b and the concentration of butyrate and NH3-N (p < 0.05). The Lachnospiraceae NK3A20 group was found to have a positive correlation with gas production parameter b, the ratio of A/P, and the concentration of butyrate, isobutyrate, isovalerate, valerate, total VFA, and NH3-N (p < 0.05), but a highly negative correlation with pH (p < 0.01). Differential metabolic pathways analysis suggested that metabolic pathways related to crude protein utilization, such as L-glutamate degradation VIII (to propanoate), L-tryptophan degradation IX, and urea cycle, increased with 5-ALA levels. In summary, including 5-ALA in the diet might improve energy and protein utilization by reducing the abundance of Actinobacteriota, the Bacteroidales BS11 gut group, the Lachnospiraceae NK3A20 group, and certain pathogenic bacteria and increasing the abundance of WPS-2.

Multivariate modular metabolic engineering and medium optimization for vitamin B12 production by Escherichia coli

Vitamin B12 is a complex compound synthesized by microorganisms. The industrial production of vitamin B12 relies on specific microbial fermentation processes. E. coli has been utilized as a host for the de novo biosynthesis of vitamin B12, incorporating approximately 30 heterologous genes. However, a metabolic imbalance in the intricate pathway significantly limits vitamin B12 production. In this study, we employed multivariate modular metabolic engineering to enhance vitamin B12 production in E. coli by manipulating two modules comprising a total of 10 genes within the vitamin B12 biosynthetic pathway. These two modules were integrated into the chromosome of a chassis cell, regulated by T7, J23119, and J23106 promoters to achieve combinatorial pathway optimization. The highest vitamin B12 titer was attained by engineering the two modules controlled by J23119 and T7 promoters. The inclusion of yeast powder to the fermentation medium increased the vitamin B12 titer to 1.52 mg/L. This enhancement was attributed to the effect of yeast powder on elevating the oxygen transfer rate and augmenting the strain's isopropyl-β-d-1-thiogalactopyranoside (IPTG) tolerance. Ultimately, vitamin B12 titer of 2.89 mg/L was achieved through scaled-up fermentation in a 5-liter fermenter. The strategies reported herein will expedite the development of industry-scale vitamin B12 production utilizing E. coli.

The epigenetic signatures of opioid addiction and physical dependence are prevented by D-cysteine ethyl ester and betaine

We have reported that D,L-thiol esters, including D-cysteine ethyl ester (D-CYSee), are effective at overcoming opioid-induced respiratory depression (OIRD) in rats. Our on-going studies reveal that co-injections of D-CYSee with multi-day morphine injections markedly diminish spontaneous withdrawal that usually occurs after cessation of multiple injections of morphine in rats. Chronically administered opioids are known (1) to alter cellular redox status, thus inducing an oxidative state, and (2) for an overall decrease in DNA methylation, therefore resulting in the transcriptional activation of previously silenced long interspersed elements (LINE-1) retrotransposon genes. The first objective of the present study was to determine whether D-CYSee and the one carbon metabolism with the methyl donor, betaine, would maintain redox control and normal DNA methylation levels in human neuroblastoma cell cultures (SH-SY5Y) under overnight challenge with morphine (100 nM). The second objective was to determine whether D-CYSee and/or betaine could diminish the degree of physical dependence to morphine in male Sprague Dawley rats. Our data showed that overnight treatment with morphine reduced cellular GSH levels, induced mitochondrial damage, decreased global DNA methylation, and increased LINE-1 mRNA expression. These adverse effects by morphine, which diminished the reducing capacity and compromised the maintenance of the membrane potential of SH-SY5Y cells, was prevented by concurrent application of D-CYSee (100 µM) or betaine (300 µM). Furthermore, our data demonstrated that co-injections of D-CYSee (250 μmol/kg, IV) and to a lesser extent, betaine (250 μmol/kg, IV), markedly diminished the development of physical dependence induced by multi-day morphine injections (escalating daily doses of 10-30 mg/kg, IV), as assessed by the lesser number of withdrawal phenomena elicited by the injection of the opioid receptor antagonist, naloxone (1.5 mg/kg, IV). These findings provide evidence that D-CYSee and betaine prevent the appearance of redox alterations and epigenetic signatures commonly seen in neural cells involved in opioid physical dependence/addiction, and lessen development of physical dependence to morphine.