Sex differences in hepatic one-carbon metabolism

Dietary folic acid intake, 13 genetic variants and other factors with red blood cell folate concentration in pregnancy-preparing population

PURPOSE

This study aims to evaluate a combined effect of dietary folic acid intake, multiple genetic polymorphisms in folate metabolism, and other environmental factors on red blood cell (RBC) folate concentration in pregnancy-preparing population.

METHODS

519 pregnancy-preparing subjects (260 couples) were investigated. Dietary intake was measured by 3-day dietary recalls. 13 Single Nucleotide polymorphisms (SNPs) reported in association with one-carbon metabolism including the methylenetetrahydrofolate reductase (MTHFR) C677T and A1298C were genotyped. RBC folate concentration was measured using chemiluminescence assay. Hierarchical regression was applied for covariate selection. Factors showed significance(p < 0.0125) on RBC folate level was included for prediction model construction and R2 estimation. Validation cohort analysis was performed as post-hoc analysis if applicable.

RESULTS

The median RBC folate was 212.8 ng/ml. Only 10% took folic acid supplementation within three months. Based on hierarchical selection, folic acid supplementation, genetic polymorphism (especially TT genotype of MTHFR C677T), serum folate level were determinants of the variance of RBC folate concentrations, with adjusted R2 of 0.178-0.242. MTHFR A1298C polymorphism, sex difference with other socio-demographic and lifestyle factors (age, BMI, alcohol drinking, smoking, education, occupation) explained little to change in RBC folate level. Validation in another sub-cohort(n = 8105) had adjusted R2 of 0.273.

CONCLUSION

In pregnancy-preparing subjects, folic acid supplementation, serum folate level and TT allele of MTHFR C677T polymorphism were determinants of the total variance of RBC folate level, which explained 19.8% variance in our subjects and 27.3% in the validation cohort. Food folate intake, sex and other environmental factors explained little to RBC folate level.

Longitudinal Analysis of One-Carbon Metabolism-Related Metabolites in Maternal and Cord Blood of Japanese Pregnant Women

One-carbon metabolism (OCM) is a complex and interconnected network that undergoes drastic changes during pregnancy. In this study, we investigated the longitudinal distribution of OCM-related metabolites in maternal and cord blood and explored their relationships. Additionally, we conducted cross-sectional analyses to examine the interrelationships among these metabolites. This study included 146 healthy pregnant women who participated in the Chiba Study of Mother and Child Health. Maternal blood samples were collected during early pregnancy, late pregnancy, and delivery, along with cord blood samples. We analyzed 18 OCM-related metabolites in serum using stable isotope dilution liquid chromatography/tandem mass spectrometry. We found that serum S-adenosylmethionine (SAM) concentrations in maternal blood remained stable throughout pregnancy. Conversely, S-adenosylhomocysteine (SAH) concentrations increased, and the total homocysteine/total cysteine ratio significantly increased with advancing gestational age. The betaine/dimethylglycine ratio was negatively correlated with total homocysteine in maternal blood for all sampling periods, and this correlation strengthened with advances in gestational age. Most OCM-related metabolites measured in this study showed significant positive correlations between maternal blood at delivery and cord blood. These findings suggest that maternal OCM status may impact fetal development and indicate the need for comprehensive and longitudinal evaluations of OCM during pregnancy.

A metabolic atlas of mouse aging

Humans are living longer, but this is accompanied by an increased incidence of age-related chronic diseases. Many of these diseases are influenced by age-associated metabolic dysregulation, but how metabolism changes in multiple organs during aging in males and females is not known. Answering this could reveal new mechanisms of aging and age-targeted therapeutics. In this study, we describe how metabolism changes in 12 organs in male and female mice at 5 different ages. Organs show distinct patterns of metabolic aging that are affected by sex differently. Hydroxyproline shows the most consistent change across the dataset, decreasing with age in 11 out of 12 organs investigated. We also developed a metabolic aging clock that predicts biological age and identified alpha-ketoglutarate, previously shown to extend lifespan in mice, as a key predictor of age. Our results reveal fundamental insights into the aging process and identify new therapeutic targets to maintain organ health.

The Role of One-Carbon Metabolism and Methyl Donors in Medically Assisted Reproduction: A Narrative Review of the Literature

One-carbon (1-C) metabolic deficiency impairs homeostasis, driving disease development, including infertility. It is of importance to summarize the current evidence regarding the clinical utility of 1-C metabolism-related biomolecules and methyl donors, namely, folate, betaine, choline, vitamin B12, homocysteine (Hcy), and zinc, as potential biomarkers, dietary supplements, and culture media supplements in the context of medically assisted reproduction (MAR). A narrative review of the literature was conducted in the PubMed/Medline database. Diet, ageing, and the endocrine milieu of individuals affect both 1-C metabolism and fertility status. In vitro fertilization (IVF) techniques, and culture conditions in particular, have a direct impact on 1-C metabolic activity in gametes and embryos. Critical analysis indicated that zinc supplementation in cryopreservation media may be a promising approach to reducing oxidative damage, while female serum homocysteine levels may be employed as a possible biomarker for predicting IVF outcomes. Nonetheless, the level of evidence is low, and future studies are needed to verify these data. One-carbon metabolism-related processes, including redox defense and epigenetic regulation, may be compromised in IVF-derived embryos. The study of 1-C metabolism may lead the way towards improving MAR efficiency and safety and ensuring the lifelong health of MAR infants.

Dietary Intakes of Choline and Betaine and Incidence of Type 2 Diabetes: Tehran Lipid and Glucose Study

Background: Our knowledge for the possible link between choline and betaine and the risk of type 2 diabetes (T2D) is very limited and contradictory. This study aimed to investigate the prospective association of dietary choline and betaine intakes with the risk of T2D in a group of Tehranian adults. Methods: In this prospective study, 6022 eligible subjects aged ≥18 years were chosen from the participants of the Tehran Lipid and Glucose Study in a secondary analysis. Diet was assessed based on a valid and reliable semiquantitative food frequency questionnaire. At baseline and follow-up examinations, biochemical and anthropometric variables were assessed. Multivariable Cox proportional hazard regression models was used to estimate the new onset of T2D concerning choline and betaine intake. Results: The mean age ± SD of 2707 men and 3315 women were, respectively, 41.4 ± 14.2 and 39.1 ± 13.1. During a median follow-up of 6.63 years, 528 cases of T2D incidence were diagnosed. Participants with a higher intake of choline had a higher intake of protein, fiber, and B12 and a lower intake of energy and carbohydrates. After controlling of confounders a significant positive association was observed between choline intake and the hazard ratio (HR) of T2D across quartiles of choline intake [HR (CI) in the fourth quartile: 1.25 (1.14-1.38), P trend = 0.01], but this significant finding was not reported for betaine intake. For every 100 milligram increase in choline consumption, the HR of T2D increased significantly in all age, sex, and BMI subgroups. Conclusions: Choline consumption increased the risk of T2D in total population and subgroups. No statistically significant association was found between dietary betaine intake and the risk of T2D in total population and subgroups.

Maternal-Periconceptional Vitamin B12 Deficiency in Wistar Rats Leads to Sex-Specific Programming for Cardiometabolic Disease Risk in the Next Generation

BACKGROUND

Maternal vitamin B12 deficiency plays a vital role in fetal programming, as corroborated by previous studies on murine models and longitudinal human cohorts.

OBJECTIVES

This study assessed the effects of diet-induced maternal vitamin B12 deficiency on F1 offspring in terms of cardiometabolic health and normalization of these effects by maternal-periconceptional vitamin B12 supplementation.

METHODS

A diet-induced maternal vitamin B12 deficient Wistar rat model was generated in which female rats were either fed a control AIN-76A diet (with 0.01 g/kg vitamin B12) or the same diet with vitamin B12 removed. Females from the vitamin B12-deficient group were mated with males on the control diet. A subset of vitamin B12-deficient females was repleted with vitamin B12 on day 1 of conception. The offspring in the F1 generation were assessed for changes in body composition, plasma biochemistry, and molecular changes in the liver. A multiomics approach was used to obtain a mechanistic insight into the changes in the offspring liver.

RESULTS

We showed that a 36% reduction in plasma vitamin B12 levels during pregnancy in F0 females can lead to continued vitamin B12 deficiency (60%-70% compared with control) in the F1 offspring and program them for cardiometabolic adversities. These adversities, such as high triglycerides and low high-density lipoprotein cholesterol, were seen only among F1 males but not females. DNA methylome analysis of the liver of F1 3-mo-old offspring highlights sexual dimorphism in the alteration of methylation status of genes critical to signaling processes. Proteomics and targeted metabolomics analysis confirm that sex-specific alterations occur through modulations in PPAR signaling and steroid hormone biosynthesis pathway. Repletion of deficient mothers with vitamin B12 at conception normalizes most of the molecular and biochemical changes.

CONCLUSIONS

Maternal vitamin B12 deficiency has a programming effect on the next generation and increases the risk for cardiometabolic syndrome in a sex-specific manner. Normalization of the molecular risk markers on vitamin B12 supplementation indicates a causal role.

Correlation of Nonalcoholic Fatty Liver Disease with Dietary Folate and Serum Folate in U.S. Adults: Cross-Sectional Analyses from National Health and Nutrition Examination Survey 2009-2018

Background and Aims: Nonalcoholic fatty liver disease (NAFLD) is a global health problem, and dietary intervention is still considered one of the primary interventions. This study aimed to examine cross-sectional associations between dietary and serum levels of folate and NAFLD. Methods: We conducted a study of 7543 adults who participated in the National Health and Nutrition Examination Survey, 2009-2018. NAFLD status was determined by a fatty liver index (FLI) value ≥60. Multivariable logistic regression models were used to estimate associations between folate and NAFLD. Results: Almost half (45%) of the patients were classified as having NAFLD based on the FLI. In the fully adjusted model, participants in the highest quartile of dietary total folate and food folate were found to have a lower prevalence of NAFLD than those in the lowest quartile [odds ratio (OR)quartile 4 versus 1 = 0.582; 95% confidence interval (CI) = 0.350-0.968; and ORquartile 4 versus 1 = 0.737; 95% CI = 0.611-0.888, respectively], and the fourth quartile values of serum total folate and 5-methyl-tetrahydrofolate were significantly negatively associated with NAFLD prevalence (ORquartile 4 versus 1 = 0.664; 95% CI = 0.495-0.891; and ORquartile 4 versus 1 = 0.712; 95% CI = 0.532-0.954, respectively). Subgroup analyses revealed that this beneficial association was more significant in women (ORquartile 4 versus 1 = 0.526; 95% CI = 0.329-0.843; pinteraction < 0.001) than in men (ORquartile 4 versus 1 = 0.805; 95% CI = 0.546-1.186). Conclusions: Higher dietary folate intake and serum folate levels are associated with a lower NAFLD prevalence among U.S. adults and the trend is more pronounced among women, indicating opportunities for dietary NAFLD interventions.

Serum 5-Methyltetrahydrofolate Status Is Associated with One-Carbon Metabolism-Related Metabolite Concentrations and Enzyme Activity Indicators in Young Women

Maintaining optimal one-carbon metabolism (OCM) is essential for health and pregnancy. In this cross-sectional study, folate status was assessed based on 5-methyltetrahydrofolate (5-MTHF) levels, and the association between 5-MTHF and OCM-related metabolites was investigated in 227 female Japanese university students aged 18-25 years. The participants were divided into high and low 5-MTHF groups based on their folate status. Serum samples of the participants were collected while they were fasting, and 18 OCM-related metabolites were measured using stable-isotope dilution liquid chromatography-electrospray tandem mass spectrometry. The association between serum 5-MTHF and OCM-related metabolite concentrations was assessed using Spearman's rank correlation coefficient. Serum 5-MTHF concentrations were negatively correlated with total homocysteine (tHcy) concentrations and positively correlated with S-adenosylmethionine (SAM) and total cysteine (tCys) concentrations. Serum 5-MTHF concentrations demonstrated a stronger negative correlation with tHcy/tCys than with tHcy alone. The negative correlation between betaine and tHcy concentrations was stronger in the low 5-MTHF group than in the high 5-MTHF group. The 5-MTHF status could be linked to Hcy flux into the transsulfuration pathway via SAM. Therefore, the tHcy/tCys ratio may be a more sensitive indicator of the 5-MTHF status than tHcy alone. Furthermore, a low 5-MTHF status can enhance Hcy metabolism via betaine.

Hyperhomocysteinemia in men and women of married couples with reproductive disorders. What is the difference?

Hyperhomocysteinemia (HHcy) is an autosomal recessive inherited metabolic disease caused by variations in folate metabolism genes, characterized by impaired methionine metabolism and accumulation of homocysteine (Hcy) in the blood serum. It was shown that men usually have higher plasma Hcy levels than women, but have not yet assessed the leading factors of these differences, which is important for the development of personalized protocols for the prevention of folate metabolism disorders in couples with reproductive disorders. This study aimed to analyze the effect of intergenic and gene-factor interactions on the risk of developing HHcy in men and women of married couples with reproductive disorders. In our study were involved 206 married Caucasian couples (206 males and 206 females) from central regions of Ukraine with early pregnancy losses in the anamnesis. We found that the incidence of HHcy in men was significantly higher than in women. Gender differences in folic acid and vitamin B12 levels were identified. The best predictors of HHcy in men (MTRR (A66G), MTHFR (C677T), MTR (A2756G), vitamin B12 level) and in women (MTHFR (C677T), MTR (A2756G), vitamin B12 level) were selected by binary logistic regression. There was no significant difference in the distribution of genotypes by the studied gene variants when comparing men and women with HHcy. Our findings demonstrate that there is a gender difference in the development of HHcy. This difference is caused by intergenic interaction and by environmental factors, in particular, nutrition and vitamins consumption.

Pregnancy homocysteine and cobalamin status predict childhood metabolic health in the offspring

BACKGROUND

Inadequate pregnancy cobalamin status has been associated with adverse offspring metabolic health in Indian and Nepalese studies. Studies of pregnancy cobalamin status and mid-childhood health outside of Asia are scarce.

METHODS

Associations between pregnancy fasting plasma total homocysteine (tHcy), cobalamin status (plasma cobalamin, holotranscobalamin (holoTC), methylmalonic acid (MMA)) and mid-childhood metabolic score (MetSco) ((including fat mass index (zFMI), homeostatic model assessment of insulin resistance (zHOMA-IR) and dyslipidemia (zTG - zHDLc)/2) z-scores)) were investigated in a prospective study of 293 mother-child dyads.

RESULTS

Highest versus low-mid pregnancy tHcy tertile was associated with higher mid-childhood MetSco, specifically with higher child zFMI. Stratifying by sex, the maternal tHcy-child MetSco association was limited to boys and confirmed for zFMI and zHOMA-IR. The maternal tHcy-child zFMI association was not mediated by birth weight z-score. First trimester plasma cobalamin was not associated with child outcomes, but other indicators of cobalamin status were. Lowest versus mid-high plasma holoTC tertile was associated with MetSco (specifically zFMI and zHOMA-IR) and highest versus low-mid plasma MMA tertile with higher MetSco and dyslipidemia in boys.

CONCLUSIONS

Moderately elevated pregnancy tHcy and low cobalamin status were associated with mid-childhood metabolic score in boys. The pregnancy tHcy-child zFMI association was not mediated by birth weight.

IMPACT

Fasting plasma total homocysteine (tHcy) during pregnancy and low cobalamin status during early pregnancy are associated with mid-childhood metabolic score and its components in the offspring. These findings were only significant in male offspring. The study provides new evidence that impaired one carbon metabolism during pregnancy is associated with negative health outcomes in the offspring, in a population with low prevalence of cobalamin deficiency. The maternal-offspring associations were observed in the functional markers of cobalamin status (holotranscobalamin and methylmalonic acid) and tHcy, not with plasma cobalamin concentration. Screening for low pregnancy cobalamin status should be considered.

Serum metabolomic analysis of the dose-response effect of dietary choline in overweight male cats fed at maintenance energy requirements

Choline participates in methyl group metabolism and has been recognized for its roles in lipid metabolism, hepatic health and muscle function in various species. Data regarding the impacts of choline on feline metabolic pathways are scarce. The present study investigated how choline intake affects the metabolomic profile of overweight cats fed at maintenance energy. Overweight (n = 14; body condition score:6-8/9) male adult cats were supplemented with five doses of choline in a 5x5 Latin Square design. Cats received a daily dose of choline on extruded food (3620 mg choline/kg diet) for three weeks at maintenance energy requirements (130 kcal/kgBW0.4). Doses were based on body weight (BW) and the daily recommended allowance (RA) for choline for adult cats (63 mg/kg BW0.67). Treatment groups included: Control (no additional choline, 1.2 x NRC RA, 77 mg/kg BW0.67), 2 x NRC RA (126 mg/kg BW0.67), 4 x NRC RA (252 mg/kg BW0.67), 6 x RA (378 mg/kg BW0.67), and 8 x NRC RA (504 mg/kg BW0.67). Serum was collected after an overnight fast at the end of each treatment period and analyzed for metabolomic parameters through nuclear magnetic resonance (NMR) spectroscopy and direct infusion mass spectrometry (DI-MS). Data were analyzed using GLIMMIX, with group and period as random effects, and dose as the fixed effect. Choline up to 8 x NRC RA was well-tolerated. Choline at 6 and 8 x NRC RA resulted in greater concentrations of amino acids and one-carbon metabolites (P < 0.05) betaine, dimethylglycine and methionine. Choline at 6 x NRC RA also resulted in greater phosphatidylcholine and sphingomyelin concentrations (P < 0.05). Supplemental dietary choline may be beneficial for maintaining hepatic health in overweight cats, as it may increase hepatic fat mobilization and methyl donor status. Choline may also improve lean muscle mass in cats. More research is needed to quantify how choline impacts body composition.

Sex-Specific miRNA Differences in Liquid Biopsies from Subjects with Solid Tumors and Healthy Controls

Dysregulation of epigenetic mechanisms has been recognized to play a crucial role in cancer development, but these mechanisms vary between sexes. Therefore, we focused on sex-specific differences in the context of cancer-based data from a recent study. A total of 12 cell-free DNA methylation targets in CpG-rich promoter regions and 48 miRNAs were analyzed by qPCR in plasma samples from 8 female and 7 male healthy controls as well as 48 female and 80 male subjects with solid tumors of the bladder, brain, colorectal region (CRC), lung, stomach, pancreas, and liver. Due to the small sample size in some groups and/or the non-balanced distribution of men and women, sex-specific differences were evaluated statistically only in healthy subjects, CRC, stomach or pancreas cancer patients, and all cancer subjects combined (n female/male-8/7, 14/14, 8/15, 6/6, 48/80, respectively). Several miRNAs with opposing expressions between the sexes were observed for healthy subjects (miR-17-5p, miR-26b-5p); CRC patients (miR-186-5p, miR-22-3p, miR-22-5p, miR-25-3p, miR-92a-3p, miR-16-5p); stomach cancer patients (miR-133a-3p, miR-22-5p); and all cancer patients combined (miR-126-3p, miR-21-5p, miR-92a-3p, miR-183-5p). Moreover, sex-specific correlations that were dependent on cancer stage were observed in women (miR-27a-3p) and men (miR-17-5p, miR-20a-5p). Our results indicate the complex and distinct role of epigenetic regulation, particularly miRNAs, depending not only on the health status but also on the sex of the patient. The same miRNAs could have diverse effects in different tissues and opposing effects between the biological sexes, which should be considered in biomarker research.

Associations between plasma sulfur amino acids and specific fat depots in two independent cohorts: CODAM and The Maastricht Study

PURPOSE

Sulfur amino acids (SAAs) have been associated with obesity and obesity-related metabolic diseases. We investigated whether plasma SAAs (methionine, total cysteine (tCys), total homocysteine, cystathionine and total glutathione) are related to specific fat depots.

METHODS

We examined cross-sectional subsets from the CODAM cohort (n = 470, 61.3% men, median [IQR]: 67 [61, 71] years) and The Maastricht Study (DMS; n = 371, 53.4% men, 63 [55, 68] years), enriched with (pre)diabetic individuals. SAAs were measured in fasting EDTA plasma with LC-MS/MS. Outcomes comprised BMI, skinfolds, waist circumference (WC), dual-energy X-ray absorptiometry (DXA, DMS), body composition, abdominal subcutaneous and visceral adipose tissues (CODAM: ultrasound, DMS: MRI) and liver fat (estimated, in CODAM, or MRI-derived, in DMS, liver fat percentage and fatty liver disease). Associations were examined with linear or logistic regressions adjusted for relevant confounders with z-standardized primary exposures and outcomes.

RESULTS

Methionine was associated with all measures of liver fat, e.g., fatty liver disease [CODAM: OR = 1.49 (95% CI 1.19, 1.88); DMS: OR = 1.51 (1.09, 2.14)], but not with other fat depots. tCys was associated with overall obesity, e.g., BMI [CODAM: β = 0.19 (0.09, 0.28); DMS: β = 0.24 (0.14, 0.34)]; peripheral adiposity, e.g., biceps and triceps skinfolds [CODAM: β = 0.15 (0.08, 0.23); DMS: β = 0.20 (0.12, 0.29)]; and central adiposity, e.g., WC [CODAM: β = 0.16 (0.08, 0.25); DMS: β = 0.17 (0.08, 0.27)]. Associations of tCys with VAT and liver fat were inconsistent. Other SAAs were not associated with body fat.

CONCLUSION

Plasma concentrations of methionine and tCys showed distinct associations with different fat depots, with similar strengths in the two cohorts.

De novo serine biosynthesis from glucose predicts sex-specific response to antifolates in non-small cell lung cancer cell lines

Lung cancer is the leading cause of cancer-related death. Intriguingly, males with non-small cell lung cancer (NSCLC) have a higher mortality rate than females. Here, we investigated the role of serine metabolism as a predictive marker for sensitivity to the antifolate pemetrexed in male and female NSCLC cell lines. Using [13C6] glucose tracing in NSCLC cell lines, we found that a subset of male cells generated significantly more serine from glucose than female cells. Higher serine biosynthesis was further correlated with increased sensitivity to pemetrexed in male cells only. Concordant sex differences in metabolic gene expression were evident in NSCLC and pan-cancer transcriptome datasets, suggesting a potential mechanism with wide-reaching applicability. These data were further validated by integrating antifolate drug cytotoxicity and metabolic pathway transcriptome data from pan-cancer cell lines. Together, these findings highlight the importance of considering sex differences in cancer metabolism to improve treatment for all patients.

Densest subgraph-based methods for protein-protein interaction hot spot prediction

Background

Hot spots play an important role in protein binding analysis. The residue interaction network is a key point in hot spot prediction, and several graph theory-based methods have been proposed to detect hot spots. Although the existing methods can yield some interesting residues by network analysis, low recall has limited their abilities in finding more potential hot spots.

Result

In this study, we develop three graph theory-based methods to predict hot spots from only a single residue interaction network. We detect the important residues by finding subgraphs with high densities, i.e., high average degrees. Generally, a high degree implies a high binding possibility between protein chains, and thus a subgraph with high density usually relates to binding sites that have a high rate of hot spots. By evaluating the results on 67 complexes from the SKEMPI database, our methods clearly outperform existing graph theory-based methods on recall and F-score. In particular, our main method, Min-SDS, has an average recall of over 0.665 and an f2-score of over 0.364, while the recall and f2-score of the existing methods are less than 0.400 and 0.224, respectively.

Conclusion

The Min-SDS method performs best among all tested methods on the hot spot prediction problem, and all three of our methods provide useful approaches for analyzing bionetworks. In addition, the densest subgraph-based methods predict hot spots with only one residue interaction network, which is constructed from spatial atomic coordinate data to mitigate the shortage of data from wet-lab experiments.

Biomarkers of the transsulfuration pathway and risk of renal cell carcinoma in the European Prospective Investigation into Cancer and Nutrition (EPIC) study

Previous studies have suggested that components of one-carbon metabolism, particularly circulating vitamin B6, have an etiological role in renal cell carcinoma (RCC). Vitamin B6 is a cofactor in the transsulfuration pathway. We sought to holistically investigate the role of the transsulfuration pathway in RCC risk. We conducted a nested case-control study (455 RCC cases and 455 matched controls) within the European Prospective Investigation into Cancer and Nutrition (EPIC) study. Plasma samples from the baseline visit were analyzed for metabolites of the transsulfuration pathway, including pyridoxal 5'-phosphate (PLP, the biologically active form of vitamin B6), homocysteine, serine, cystathionine, and cysteine, in addition to folate. Bayesian conditional logistic regression was used to estimate associations of metabolites with RCC risk as well as interactions with established RCC risk factors. Circulating PLP and cysteine were inversely associated with RCC risk, and these associations were not attenuated after adjustment for other transsulfuration metabolites (odds ratio (OR) and 90% credible interval (CrI) per 1 SD increase in log concentration: 0.76 [0.66, 0.87]; 0.81 [0.66, 0.96], respectively). A comparison of joint metabolite profiles suggested substantially greater RCC risk for the profile representative of low overall transsulfuration function compared to high function (OR 2.70 [90% CrI 1.26, 5.70]). We found some statistical evidence of interactions of cysteine with body mass index, and PLP and homocysteine with smoking status, on their associations with RCC risk. In conclusion, we found evidence suggesting that the transsulfuration pathway may play a role in metabolic dysregulation leading to RCC development.

Chemotactic cytokines secreted from Kupffer cells contribute to the sex-dependent susceptibility to non-alcoholic fatty liver diseases in mice

AIMS

The global prevalence of non-alcoholic fatty liver disease (NAFLD) has rapidly increased over the last decade due to an elevated occurrence of metabolic syndromes. Importantly, the prevalence and severity of NAFLD is higher in men than in women. Therefore, in the present study we endeavored to identify the mechanistic disparity between male and female mice.

MAIN METHODS

Global gene transcriptomics analysis was done with the high-fat diet (HFD)-induced NAFLD model of male, female, and ovariectomized (OVX) female mice. The expression of CCL2, CXCL2, and CXCL10 in mRNA level and serum protein level was done by qPCR and ELISA each. Immunohistochemistry staining was used to observe hepatic immune cell infiltration. To analyzing portion of immune cells, flow cytometry was done with isolated liver cells from HFD-fed male and female mice. Primary mouse liver cells were isolated from male and female mice for in vitro studies.

KEY FINDINGS

We identified sex differences in inflammatory chemokines, CCL2, CXCL2, and CXCL10, with the expression of these chemokines enhanced in male and OVX, but not in female, mice after HFD feeding. Resident Kupffer cells (KCs) were identified as the major source of production of CCL2, CXCL2, and CXCL10 in the mouse NAFLD model. Notably, KCs obtained from male mice expressed higher levels of chemokines than those from female mice, indicating that KCs may mediate the sex discrepancy in NAFLD progression.

SIGNIFICANCE

Our findings offer new insights into the pathology of sex-specific differences in NAFLD, involving chemokines and KCs.

Methyl Group Metabolism in Differentiation, Aging, and Cancer

Methyl group metabolism belongs to a relatively understudied field of research. Its importance lies in the fact that methyl group metabolic pathways are crucial for the successful conversion of dietary nutrients into the basic building blocks to carry out any cellular methylation reaction. Methyl groups play essential roles in numerous cellular functions such as DNA methylation, nucleotide- and protein biosynthesis. Especially, DNA methylation is responsible for organizing the genome into transcriptionally silent and active regions. Ultimately, it is this proper annotation that determines the quality of expression patterns required to ensure and shape the phenotypic integrity and function of a highly specialized cell type. Life is characterized by constantly changing environmental conditions, which are addressed by changes in DNA methylation. This relationship is increasingly coming into focus as it is of fundamental importance for differentiation, aging, and cancer. The stability and permanence of these metabolic processes, fueling the supplementation of methyl groups, seem to be important criteria to prevent deficiencies and erosion of the methylome. Alterations in the metabolic processes can lead to epigenetic and genetic perturbations, causative for diverse disorders, accelerated aging, and various age-related diseases. In recent decades, the intake of methyl group compounds has changed significantly due to, e.g., environmental pollution and food additives. Based on the current knowledge, this review provides a brief overview of the highly interconnected relationship between nutrition, metabolism, changes in epigenetic modifications, cancer, and aging. One goal is to provide an impetus to additionally investigate changes in DNA methylation as a possible consequence of an impaired methyl group metabolism.

Associations of plasma betaine, plasma choline, choline intake and MTHFR polymorphism (rs1801133) with anthropometric parameters of healthy adults are sex-dependent

OBJECTIVE

Choline and its metabolites seem to have relationships with body mass index (BMI), body fat, and body weight, but research results have proved inconsistent. We thus investigated the associations of plasma levels of TMAO, choline, and betaine, with anthropometric measurements, including modulatory effects of genetics and diet.

METHODS

The study was performed on a group of 421 adults aged 20 to 40, who had been recruited in Poland. Plasma concentrations of choline, betaine, and TMAO were determined using RP-UHPLC-ESI-MS. The following polymorphisms were genotyped using TaqMan probes: rs180113 (MTHFR), the rs70991108 (DHFR), rs2236225 (MTHFD1), and rs7946 and rs12325817 (PEMT). We employed multivariate linear regression to examine the associations between anthropometric measurements, one carbon metabolism metabolites, and genotypes.

RESULTS

Higher plasma choline was associated with higher BMI (β=0.17; p< 0.01), body weight (β=0.11; p< 0.05), body fat mass (β=0.10; p<0.05), and waist circumference (WC) (β=0.14; p<0.01), whereas higher choline intake was associated with lower body fat mass (β=-0.14; p< 0.01), and lower WC (β=-0.12; p<0.01). After stratification by sex, plasma betaine was found to be associated with BMI (β=-0.20; p<0.05) and body weight (β=-0.16; p<0.05) in men only, while choline intake was associated with body fat mass (β=-0.19; p<0.05), and WHR (β=-0.19; p<0.05), and MTHFR CC genotype was associated with WHR (β=0.15; p<0.05) in women only.

CONCLUSIONS

Higher plasma betaine and higher dietary choline are associated with lower fat mass and body weight, whereas higher plasma choline is positively associated with body weight status and adiposity. Moreover, these associations seem to be sex-specific. This article is protected by copyright. All rights reserved.

Sex-Specific Metabolic Effects of Dietary Folate Withdrawal in Wild-Type and Aldh1l1 Knockout Mice

ALDH1L1 (10-formyltetrahydrofolate dehydrogenase), an enzyme of folate metabolism, is highly expressed in the liver. It regulates the overall flux of folate-bound one-carbon groups by converting 10-formyltetrahydrofolate to tetrahydrofolate and CO2 in a NADP+-dependent reaction. Our previous study revealed that Aldh1l1 knockout (KO) mice have an altered liver metabotype with metabolic symptoms of folate deficiency when fed a standard chow diet containing 2 ppm folic acid. Here we performed untargeted metabolomic analysis of liver and plasma of KO and wild-type (WT) male and female mice fed for 16 weeks either standard or folate-deficient diet. OPLS-DA, a supervised multivariate technique that was applied to 6595 and 10,678 features for the liver and plasma datasets, respectively, indicated that genotype and diet, alone or in combination, gave distinct metabolic profiles in both types of biospecimens. A more detailed analysis of affected metabolic pathways based on most confidently identified metabolites in the liver and plasma (OL1 and OL2a ontology level) indicated that the dietary folate restriction itself does not fully recapitulate the metabolic effect of the KO. Of note, dietary folate withdrawal enhanced the metabolic perturbations linked to the ALDH1L1 loss only for a subset of metabolites. Importantly, both the ALDH1L1 loss and dietary folate deficiency produced sex-specific metabolic effects.

Severe Acute Respiratory Syndrome Coronavirus 2 Infection is Associated with Homocysteine Level and Clinical Outcomes in Ischemic Stroke Patients

BACKGROUND: Since its emergence in December 2019 and declared as pandemic in March 2020, the drastic increase in cases of coronavirus disease 2019 (COVID-19) is alarming the importance of disease monitoring in order to prevent further complication, like ischemic stroke. One of the efforts is utilizing biomarker. For instance, elevated homocysteine level, already known risk factor of ischemic stroke, is currently identified in COVID-19 patients. AIM: To assess factor associated with homocysteine level and clinical outcomes of ischemic stroke patients. Methods: A cross-sectional study was conducted at Dr. Zainoel Abidin Hospital di Indonesia between March and August 2021. Ischemic stroke patients who had physical and neurology examinations, SARS-CoV-2 RT-PCR swab, chest x-ray, electrocardiography, head CT-scan and the total homocysteine level were included. To assess the factors associated with homocysteine level and the outcomes of ischemic stroke patients, the independent Student t-test or Anova and chi-squared were used, respectively. RESULTS: We included 62 ischemic stroke patients of which 32 (51.6%) were male and the age ranged between 30 and 80 years. Out of total, 60 patients (96.8%) were survived after the hospital admission. There was a significant association between gender and having COVID-19 with homocysteine level (p=0.012 and p=0.020, respectively). Having COVID-19 was the only variable significantly associated with the outcome of the ischemic stroke patient (p=0.035). CONCLUSION: COVID-19 is associated with homocysteine level and the clinical outcome in ischemic stroke patients. Therefore, SARS-CoV-2 infection in ischemic stroke or vice versa need to be monitored closely in hospital settings.

Vitamin B12 Supplementation and Vitamin B12 Blood Serum Levels: Evaluation of Effect Modification by Gender and Smoking Status

Research suggests that high intake of supplemental vitamin B₁₂ may be associated with increased risk of cancer, with some evidence that this association may vary by gender and smoking status. This investigation evaluates if similar patterns in association are observed for data for 11,757 adults from the National Health and Nutrition Examination Survey (1999-2006). Survey-weighted multivariable-adjusted linear regression was used to evaluate the association between regular B₁₂ supplement use and log-transformed serum B₁₂ levels. Persons taking vitamin B₁₂ through a multivitamin/multimineral (MVMM) had a median supplemental intake of 12 mcg/day (Q1: 6, Q3: 25), compared to 100 mcg/day (Q1: 22, Q3: 500) for persons reporting supplemental B₁₂ intake through a MVMM-exclusive source. MVMM users had a geometric mean serum B12 26% (95% CI: 23%-30%) higher than nonusers, whereas MVMM-exclusive users' geometric mean was 61% (95% CI: 53%-70%) higher than nonusers (p-trend < 0.001). Although a positive trend (p-trend < 0.001) was observed for both men and women, the association was stronger among women (p-interaction < 0.001). No interaction was observed for smoking status (p-interaction = 0.45). B₁₂ supplementation is associated with higher levels of serum B₁₂, with significant interaction by gender but not smoking. Further work is needed to better understand the interplay of B₁₂ and gender.

Assessment of Dietary Choline Intake, Contributing Food Items, and Associations with One-Carbon and Lipid Metabolites in Middle-Aged and Elderly Adults: The Hordaland Health Study

BACKGROUND

Choline is an essential nutrient for humans and is involved in various physiologic functions. Through its metabolite betaine, it is closely connected to the one-carbon metabolism, and the fat-soluble choline form phosphatidylcholine is essential for VLDL synthesis and secretion in the liver connecting choline to the lipid metabolism. Dietary recommendations for choline are not available in the Nordic countries primarily due to data scarcity.

OBJECTIVES

The aim of this study was to investigate the dietary intake of total choline and individual choline forms, dietary sources, and the association of total choline intake with circulating one-carbon metabolites and lipids.

METHODS

We included 5746 participants in the Hordaland Health Study, a survey including community-dwelling adults born in 1925-1927 (mean age 72 y, 55% women) and 1950-1951 (mean age 48 y, 57% women). Dietary data were obtained using a 169-item FFQ, and choline content was calculated using the USDA Database for Choline Content of Common Foods, release 2. Metabolites of the one-carbon and lipid metabolism were measured in a nonfasting blood sample obtained at baseline, and the association with total choline intake was assessed using polynomial splines.

RESULTS

The geometric mean (95% prediction interval) energy-adjusted total choline intake was 260 (170, 389) mg/d, with phosphatidylcholine being the main form (44%). The major food items providing dietary choline were eggs, low-fat milk, potatoes, and leafy vegetables. Dietary total choline was inversely associated with circulating concentrations of total homocysteine, glycine, and serine and positively associated with choline, methionine, cystathionine, cysteine, trimethyllysine, trimethylamine-N-oxide, and dimethylglycine. A weak association was observed between choline intake and serum lipids.

CONCLUSIONS

Phosphatidylcholine was the most consumed choline form in community-dwelling adults in Norway. Our findings suggest that choline intake is associated with the concentration of most metabolites involved in the one-carbon and lipid metabolism.

Pharmacokinetic properties of a novel formulation of S-adenosyl-L-methionine phytate

S-adenosyl-L-methionine (SAM), the main endogenous methyl donor, is the adenosyl derivative of the amino acid methionine, which displays many important roles in cellular metabolism. It is widely used as a food supplement and in some countries is also marketed as a drug. Its interesting nutraceutical and pharmacological properties prompted us to evaluate the pharmacokinetics of a new form of SAM, the phytate salt. The product was administered orally to rats and pharmacokinetic parameters were evaluated by comparing the results with that obtained by administering the SAM tosylated form (SAM PTS). It was found that phytate anion protects SAM from degradation, probably because of steric hindrance exerted by the counterion, and that the SAM phytate displayed significant better pharmacokinetic parameters compared to SAM PTS. These results open to the perspective of the use of new salts of SAM endowed with better pharmacokinetic properties.

A comparison of complementary measures of vitamin B6 status, function, and metabolism in the European Prospective Investigation into Cancer and Nutrition (EPIC) study

BACKGROUND

Vitamin B6 insufficiency has been linked to increased risk of cancer and other chronic diseases. The circulating concentration of pyridoxal 5'-phosphate (PLP) is a commonly used measure of vitamin B6 status. Ratios of substrates indicating PLP coenzymatic function and metabolism may be useful complementary measures to further explore the role of vitamin B6 in health.

OBJECTIVES

We explored the sensitivity of 5 outcomes, namely PLP concentration, homocysteine:cysteine (Hcy:Cys), cystathionine:cysteine (Cysta:Cys), the 3´-hydroxykynurenine ratio (HKr), and the 4-pyridoxic acid ratio (PAr) to vitamin B6 intake as well as personal and lifestyle characteristics.

MEDTHODS

Dietary intake and biomarker data were collected from participants from 3 nested case-control studies within the European Prospective Investigation into Cancer and Nutrition (EPIC). Bayesian regression models assessed the associations of the 5 biomarker outcomes with vitamin B6 intake and personal and lifestyle covariates. Analogous models examined the relations of Hcy:Cys, Cysta:Cys, and HKr with PLP.

RESULTS

In total, 4608 participants were included in the analyses. Vitamin B6 intake was most strongly associated with PLP, moderately associated with Hcy:Cys, Cysta:Cys, and HKr, and not associated with PAr (fold change in marker given a doubling of vitamin B6 intake: PLP 1.60 [95% credible interval (CrI): 1.50, 1.71]; Hcy:Cys 0.87 [95% CrI: 0.84, 0.90]; Cysta:Cys 0.89 [95% CrI: 0.84, 0.94]; HKr 0.88 [95% CrI: 0.85, 0.91]; PAr 1.00 [95% CrI: 0.95, 1.05]). PAr was most sensitive to age, and HKr was least sensitive to BMI and alcohol intake. Sex and menopause status were strongly associated with all 5 markers.

CONCLUSIONS

We found that 5 different markers, capturing different aspects of vitamin B6-related biological processes, varied in their associations with vitamin B6 intake and personal and lifestyle predictors.

Nutrition, one-carbon metabolism and arsenic methylation

Exposure to arsenic (As) is a major public health concern globally. Inorganic As (InAs) undergoes hepatic methylation to form monomethyl (MMAs)- and dimethyl (DMAs)-arsenical species, facilitating urinary As elimination. MMAsIII is considerably more toxic than either InAsIII or DMAsV, and a higher proportion of MMAs in urine has been associated with risk for a wide range of adverse health outcomes. Efficiency of As methylation differs substantially between species, between individuals, and across populations. One-carbon metabolism (OCM) is a biochemical pathway that provides methyl groups for the methylation of As, and is influenced by folate and other micronutrients, such as vitamin B12, choline, betaine and creatine. A growing body of evidence has demonstrated that OCM-related micronutrients play a critical role in As methylation. This review will summarize observational epidemiological studies, interventions, and relevant experimental evidence examining the role that OCM-related micronutrients have on As methylation, toxicity of As, and risk for associated adverse health-related outcomes. There is fairly robust evidence supporting the impact of folate on As methylation, and some evidence from case-control studies indicating that folate nutritional status influences risk for As-induced skin lesions and bladder cancer. However, the potential for folate to be protective for other As-related health outcomes, and the potential beneficial effects of other OCM-related micronutrients on As methylation and risk for health outcomes are less well studied and warrant additional research.

Metabolism-Based Gene Differences in Neurons Expressing Hyperphosphorylated AT8- Positive (AT8+) Tau in Alzheimer's Disease

Metabolic adaptations in the brain are critical to the establishment and maintenance of normal cellular functions and to the pathological responses to disease processes. Here, we have focused on specific metabolic pathways that are involved in immune-mediated neuronal processes in brain using isolated neurons derived from human autopsy brain sections of normal individuals and individuals diagnosed as Alzheimer's disease (AD). Laser capture microscopy was used to select specific cell types in immune-stained thin brain sections followed by NanoString technology to identify and quantify differences in mRNA levels between age-matched control and AD neuronal samples. Comparisons were also made between neurons isolated from AD brain sections expressing pathogenic hyperphosphorylated AT8- positive (AT8+) tau and non-AT8+ AD neurons using double labeling techniques. The mRNA expression data showed unique patterns of metabolic pathway expression between the subtypes of captured neurons that involved membrane based solute transporters, redox factors, and arginine and methionine metabolic pathways. We also identified the expression levels of a novel metabolic gene, Radical-S-Adenosyl Domain1 (RSAD1) and its corresponding protein, Rsad1, that impact methionine usage and radical based reactions. Immunohistochemistry was used to identify specific protein expression levels and their cellular location in NeuN+ and AT8+ neurons. APOE4 vs APOE3 genotype-specific and sex-specific gene expression differences in these metabolic pathways were also observed when comparing neurons from individuals with AD to age-matched individuals.

Maternal plasma choline and betaine in late pregnancy and child growth up to age 8 years in the KOALA Birth Cohort Study

BACKGROUND

Sufficient choline and betaine during pregnancy are needed for fetal growth and development.

OBJECTIVES

We aimed to investigate the associations between maternal plasma choline and betaine in the third trimester of pregnancy and child growth from birth up to 8 years of age.

METHODS

Concentrations of choline and betaine were measured in plasma of 1331 pregnant women from the KOALA (Kind, Ouders en gezondheid: Aandacht voor Leefstijl en Aanleg) Birth Cohort Study in the Netherlands. Child weight and height were measured at birth and at 1 (91% complete), 2 (86%), and 6-8 y (76%). Birth weight, weight gain in the first year, and z scores for weight and height at 1 and 2 y were used as continuous outcome variables. BMI z scores at 1 and 2 y were used as continuous and dichotomous outcomes, and BMI z scores at age 6-8 y were used to study overweight at that age.

RESULTS

Each 1-µmol/L increase of maternal plasma choline was associated with a mean 20-g (95% CI: 1.1, 38.0 g) higher weight gain in the first year of life, and a higher BMI z score (β: 0.02; 95% CI: 0.00, 0.04) and slightly higher odds of BMI z score >85th percentile (OR: 1.08; 95% CI: 1.03, 1.10) at 1-2 y. Each 1-µmol/L increase of plasma betaine was associated with a mean 12-g (95% CI: 0.8, 23.9 g) higher weight gain in the first year of life and higher odds of BMI z score >85th percentile at 1-2 y (OR: 1.03; 95% CI: 1.00, 1.07). Lastly, betaine was associated with overweight at 6-8 y (OR: 1.17; 95% CI: 1.02, 1.34), only in boys.

CONCLUSIONS

Third-trimester pregnancy plasma choline and betaine were positively associated with childhood anthropometric measures. In boys, some of the associations may have persisted up to 8 y of age. Further studies may investigate the validity of maternal plasma choline and betaine concentrations as markers of maternal intake and fetal transfer.

Letrozole-Induced Polycystic Ovary Syndrome Attenuates Cystathionine-β Synthase mRNA and Protein Abundance in the Ovaries of Female Sprague Dawley Rats

BACKGROUND

Polycystic ovary syndrome (PCOS) is an endocrine disorder that affects 10% of reproductive-aged women and leads to hyperandrogenism, anovulation, and infertility. PCOS has been associated with elevated serum homocysteine as well as altered methylation status; however, characterization of one-carbon metabolism (OCM) in PCOS remains incomplete.

OBJECTIVES

The aim of our research was to assess OCM in a letrozole-induced Sprague Dawley rat model of PCOS.

METHODS

Five-week-old female rats (n = 36) were randomly assigned to letrozole [0.9 mg/kg body weight (BW)] treatment or vehicle (carboxymethylcellulose) control that was administered via subcutaneously implanted slow-release pellets every 30 d. For both treatment groups, 12 rats were randomly assigned to be euthanized during proestrus at one of the following time points: 8, 16, or 24 wk of age. Daily BW was measured and estrous cyclicity was monitored during the last 30 d of the experimental period. Ovaries were collected to assess mRNA and protein abundance of OCM enzymes.

RESULTS

Letrozole-induced rats exhibited 1.9-fold higher cumulative BW gain compared with control rats across all age groups (P < 0.0001). Letrozole reduced the time spent at proestrus (P = 0.0001) and increased time in metestrus (P < 0.0001) of the estrous cycle. Cystathionine β-synthase (Cbs) mRNA abundance was reduced in the letrozole-induced rats at 16 (59%; P < 0.05) and 24 (77%; P < 0.01) wk of age. In addition, CBS protein abundance was 32% lower in 8-wk-old letrozole-induced rats (P = 0.02). Interestingly, betaine-homocysteine S-methyltransferase mRNA abundance increased as a function of age in letrozole-induced rats (P = 0.03).

CONCLUSION

These data demonstrate that letrozole-induced PCOS Sprague Dawley rats temporally decrease the ovarian abundance of Cbs mRNA and protein in the early stages of PCOS.

Association between body mass index and arsenic methylation in three studies of Bangladeshi adults and adolescents

BACKGROUND

Water-borne arsenic (As) exposure is a global health problem. Once ingested, inorganic As (iAs) is methylated to mono-methyl (MMA) and dimethyl (DMA) arsenicals via one-carbon metabolism (OCM). People with higher relative percentage of MMA (MMA%) in urine (inefficient As methylation), have been shown to have a higher risk of cardiovascular disease and several cancers but appear to have a lower risk of diabetes and obesity in populations from the US, Mexico, and Taiwan. It is unknown if this opposite pattern with obesity is present in Bangladesh, a country with lower adiposity and higher As exposure in drinking water.

OBJECTIVE

To characterize the association between body mass index (BMI) and As methylation in Bangladeshi adults and adolescents participating in the Folic Acid and Creatine Trial (FACT); Folate and Oxidative Stress (FOX) study; and Metals, Arsenic, and Nutrition in Adolescents Study (MANAS).

METHODS

Arsenic species (iAs, MMA, DMA) were measured in urine and blood. Height and weight were measured to calculate BMI. The associations between concurrent BMI with urine and blood As species were analyzed using linear regression models, adjusting for nutrients involved in OCM such as choline. In FACT, we also evaluated the prospective association between weight change and As species.

RESULTS

Mean BMIs were 19.2/20.4, 19.8/21.0, and 17.7/18.7 kg/m2 in males/females in FACT, FOX, and MANAS, respectively. BMI was associated with As species in female but not in male participants. In females, after adjustment for total urine As, age, and plasma folate, the adjusted mean differences (95% confidence) in urinary MMA% and DMA% for a 5 kg/m2 difference in BMI were -1.21 (-1.96, -0.45) and 2.47 (1.13, 3.81), respectively in FACT, -0.66 (-1.56, 0.25) and 1.43 (-0.23, 3.09) in FOX, and -0.59 (-1.19, 0.02) and 1.58 (-0.15, 3.30) in MANAS. The associations were attenuated after adjustment for choline. Similar associations were observed with blood As species. In FACT, a 1-kg of weight increase over 2 to 10 (mean 5.4) years in males/females was prospectively associated with mean DMA% that was 0.16%/0.19% higher.

DISCUSSION

BMI was negatively associated with MMA% and positively associated with %DMA in females but not males in Bangladesh; associations were attenuated after plasma choline adjustment. These findings may be related to the role of body fat on estrogen levels that can influence one-carbon metabolism, e.g. by increasing choline synthesis. Research is needed to determine whether the associations between BMI and As species are causal and their influence on As-related health outcomes.

Nutrition, one-carbon metabolism and arsenic methylation in Bangladeshi adolescents

BACKGROUND

Over 57 million people in Bangladesh are chronically exposed to arsenic-contaminated drinking water. Ingested inorganic arsenic (InAs) undergoes hepatic methylation generating monomethyl- (MMAs) and dimethyl- (DMAs) arsenic species in a process that facilitates urinary As (uAs) elimination. One-carbon metabolism (OCM), a biochemical pathway that is influenced by folate and vitamin B12, facilitates the methylation of As. OCM also supports nucleotide and amino acid synthesis, particularly during periods of rapid growth such as adolescence. While folate supplementation increases As methylation and lowers blood As (bAs) in adults, little data is available for adolescents.

OBJECTIVES

To examine the associations between OCM-related micronutrients and As methylation in Bangladeshi adolescents chronically exposed to As-contaminated drinking water.

METHODS

We conducted a cross-sectional study of 679 Bangladeshi adolescents, including 320 boys and 359 girls aged 14-16 years. Nutritional status was assessed by red blood cell (RBC) folate, plasma folate, plasma B12 and homocysteine (Hcys). Arsenic-related outcomes included blood arsenic (bAs), urinary arsenic (uAs), and urinary arsenic metabolites expressed as a percentage of total urinary As: %InAs, %MMAs, %DMAs.

RESULTS

Boys had significantly lower B12, higher Hcys, higher bAs, higher uAs, higher %MMAs, and a trend toward lower RBC folate compared to girls. Therefore, regression analyses controlling for water As and BMI were sex stratified. Among girls, RBC folate was inversely associated with bAs, plasma B12 was inversely associated with uAs, and plasma Hcys was inversely associated with %MMA. Among boys, plasma folate was inversely associated with %InAs and positively associated with %DMA, RBC folate was inversely associated with %InAs and positively associated with %MMA, while Hcys was positively associated with %InAs.

CONCLUSIONS

These findings suggest that associations between OCM nutritional status, bAs, and distribution of As metabolites in adolescents are similar to previously reported observations in adults and in children. The As methylation findings are statistically significant among boys but not among girls; this may be related to estrogen which more strongly influences OCM in females. The inverse association between Hcys and %MMA in girls is somewhat unexpected given that Hcys is known to be an indicator of impaired OCM and low folate/B12 in adults. Overall, these results indicate that the associations between OCM-related micronutrients and arsenic methylation in adolescents are generally similar to prior findings in adults, though these associations may differ by sex. Additionally, these findings suggest that more investigation into the role of Hcys in adolescent physiology is needed, perhaps particularly for girls. Additional studies are needed to evaluate the impact of OCM and As methylation on As-related adverse health outcomes (such as cancer and cardiovascular disease) in people exposed to As during adolescence.

Pharmacokinetics of Sodium and Calcium Salts of (6S)-5-Methyltetrahydrofolic Acid Compared to Folic Acid and Indirect Comparison of the Two Salts

(6S)-5-Methyltetrahydrofolic acid ((6S)-5-Methyl-THF) salts and folic acid may differ in their abilities to raise plasma (6S)-5-Methyl-THF levels. We compared the area under the curve (AUC), C_max, and T_max of plasma (6S)-5-Methyl-THF after intakes of (6S)-5-Methyl-THF-Na salt (Arcofolin^®) and folic acid. Moreover, we compared the AUCs after intakes of (6S)-5-Methyl-THF-Na and the calcium salt, (6S)-5-Methyl-THF-Ca, that were tested against folic acid in two independent studies. The study was randomized, double blind, and cross over. Twenty-four adults (12 men and 12 women) received a single oral dose of 436 µg (6S)-5-Methyl-THF-Na and an equimolar dose of folic acid (400 µg) on two kinetic days with two weeks washout period in between. The plasma concentrations of (6S)-5-Methyl-THF were measured at 9 time points between 0 and 8 h. We found that the AUC_{0–8 h} of plasma (6S)-5-Methyl-THF (mean (SD) = 126.0 (33.6) vs. 56.0 (25.3) nmol/L*h) and C_max (36.8 (10.8) vs. 11.1 (4.1) nmol/L) were higher after administration of (6S)-5-Methyl-THF-Na than after the administration of folic acid (p < 0.001 for both). These differences were present in men and women. Only administration of folic acid resulted in a transient increase in plasma unmetabolized folic acid (2.5 (2.0) nmol/L after 0.5 h and 4.7 (2.9) nmol/L after 1 h). Intake of (6S)-5-Methyl-THF-Na was safe. The ratios of the AUC_{0–8 h} for (6S)-5-Methyl-THF-Na and (6S)-5-Methyl-THF-Ca to the corresponding folic acid reference group and the delta of these AUC_{0–8 h} did not differ between the studies. In conclusion, a single oral dose of (6S)-5-Methyl-THF-Na caused higher AUC_{0–8 h} and C_max of plasma (6S)-5-Methyl-THF compared to folic acid. The Na- and Ca- salts of (6S)-5-Methyl-THF are not likely to differ in their pharmacokinetics. Further studies may investigate whether supplementation of the compounds for a longer time will lead to differences in circulating or intracellular/tissue folate concentrations.

The Association of Dietary Choline and Betaine With the Risk of Type 2 Diabetes: The Atherosclerosis Risk in Communities (ARIC) Study

OBJECTIVE

To examine the association between dietary intake of choline and betaine and the risk of type 2 diabetes.

RESEARCH DESIGN AND METHODS

Among 13,440 Atherosclerosis Risk in Communities (ARIC) study participants, the prospective longitudinal association between dietary choline and betaine intake and the risk of type 2 diabetes was assessed using interval-censored Cox proportional hazards and logistic regression models adjusted for baseline potential confounding variables.

RESULTS

Among 13,440 participants (55% women, mean age 54 [SD 7.4] years), 1,396 developed incident type 2 diabetes during median follow-up of 9 years from 1987 to 1998. There was no statistically significant association between every 1-SD increase in dietary choline and risk of type 2 diabetes (hazard ratio [HR] 1.01 [95% CI 0.87, 1.16]) nor between dietary betaine intake and the risk of type 2 diabetes (HR 1.01 [0.94, 1.10]). Those in the highest quartile of dietary choline intake did not have a statistically significant higher risk of type 2 diabetes than those in the lowest choline quartile (HR 1.09 [0.84, 1.42]); similarly, dietary betaine intake was not associated with the risk of type 2 diabetes comparing the highest quartile to the lowest (HR 1.06 [0.87, 1.29]). Among women, there was a higher risk of type 2 diabetes, comparing the highest to lowest dietary choline quartile (HR 1.54 [1.06, 2.25]), while in men, the association was null (HR 0.82 [0.57, 1.17]). Nevertheless, there was a nonsignificant interaction between high choline intake and sex on the risk of type 2 diabetes (P = 0.07). The results from logistic regression were similar.

CONCLUSIONS

Overall and among male participants, dietary choline or betaine intakes were not associated with the risk of type 2 diabetes. Among female participants, there was a trend for a modestly higher risk of type 2 diabetes among those with the highest as compared with the lowest quartile of dietary choline intake. Our study should inform clinical trials on dietary choline and betaine supplementation in relationship with the risk of type 2 diabetes.

The influence of choline treatment on behavioral and neurochemical autistic-like phenotype in Mthfr-deficient mice

Imbalanced one carbon metabolism and aberrant autophagy is robustly reported in patients with autism. Polymorphism in the gene methylenetetrahydrofolate reductase (Mthfr), encoding for a key enzyme in this pathway is associated with an increased risk for autistic-spectrum-disorders (ASDs). Autistic-like core and associated behaviors have been described, with contribution of both maternal and offspring Mthfr^+/- genotype to the different domains of behavior. Preconception and prenatal supplementation with methyl donor rich diet to human subjects and mice reduced the risk for developing autism and autistic-like behavior, respectively. Here we tested the potential of choline supplementation to Mthfr-deficient mice at young-adulthood to reduce behavioral and neurochemical changes reminiscent of autism characteristics. We show that offspring of Mthfr^+/- mothers, whether wildtype or heterozygote, exhibit autistic-like behavior, altered brain p62 protein levels and LC3-II/LC3-I levels ratio, both, autophagy markers. Choline supplementation to adult offspring of Mthfr^+/- mothers for 14 days counteracted characteristics related to repetitive behavior and anxiety both in males and in females and improved social behavior solely in male mice. Choline treatment also normalized deviant cortical levels of the autophagy markers measured in male mice. The results demonstrate that choline supplementation even at adulthood, not tested previously, to offspring of Mthfr-deficient mothers, attenuates the autistic-like phenotype. If this proof of concept is replicated it might promote translation of these results to treatment recommendation for children with ASDs bearing similar genetic/metabolic make-up.

Long-term effects of folic acid and vitamin-B12 supplementation on fracture risk and cardiovascular disease: Extended follow-up of the B-PROOF trial

BACKGROUND & AIMS

In the initial B-proof, we found inconsistent results of B vitamin supplementation. However, the debate regarding the effects of B vitamins on age-related diseases continues. Therefore, our aim was to investigate the long-term effects (5-7 years follow-up) of an intervention with folic acid and vitamin-B12 supplementation on fracture and cardiovascular disease risk.

METHODS

Extended follow-up of the B-PROOF trial, a multi-center, double-blind randomized placebo-controlled trial designed to assess the effect of 2-3 years daily supplementation with folic acid (400 μg) and vitamin-B12 (500 μg) versus placebo (n = 2,919). Primary outcome was verified self-reported fracture incidence and secondary outcomes were self-reported cardiovascular endpoints, which were collected through a follow-up questionnaires Proportional hazard analyses was used for the effect of the intervention on risk of fracture(s) and logistic regression for the effect of the intervention on risk of cardiovascular disease.

RESULTS

A total of 1,298 individuals (44.5%) participated in the second follow-up round with median of 54 months [51-58], (n = 662 and n = 636, treatment versus placebo group). Median age at baseline was 71.0 years [68.0-76.0] for both groups. No effect was observed of the intervention on osteoporotic fracture or any fracture risk after a follow-up (HR: 0.99, 95% CI: 0.62-1.59 and HR: 0.77; 95% CI: 0.50-1.19, respectively), nor on cardiovascular or cerebrovascular disease risk (OR: 1.05; 95%CI: 0.80-1.44 and OR: 0.85; 95%CI: 0.50-1.45, respectively). Potential interaction by baseline homocysteine concentration was observed for osteoporotic- and any fracture (p = 0.10 and 0.06 respectively), which indicated a significantly lower risk of any fracture in the treatment group with higher total homocysteine concentrations (>15.1 μmol/l). No age-dependent effects were present.

CONCLUSIONS

This study supports and extends previous null-findings of the B-PROOF trial and shows that supplementation of folic acid and vitamin-B12 has no effect on fracture risk, nor on cardiovascular disease in older individuals over a longer follow-up period. However, B-vitamin supplementation may be beneficial in reducing fractures in individuals with high total homocysteine concentrations, a finding which needs to be replicated.

Sex-Specific Metabolic Changes in Peripheral Organs of Diabetic Mice

Diabetes mellitus (DM) can cause systemic metabolic disorders, but the impact of gender on DM-related metabolic changes is rarely reported. Herein, we analyzed metabolic alterations in the heart, liver, and kidney of male and female mice from normal to diabetes via a ¹H NMR-based metabolomics method and aimed to investigate sex-specific metabolic mechanisms underlying the onset and development of diabetes and its complications. Our results demonstrate that male mice had more significant metabolic disorders from normal to diabetes than female mice. Moreover, the kidney was found as the major organ of metabolic disorders during the development of diabetes, followed by the liver and heart. These altered metabolites were mainly implicated in energy metabolism as well as amino acid, choline, and nucleotide metabolism. Therefore, this study suggests that the kidney is the primary organ affected by diabetes in a sex-specific manner, which provides a metabolic view on the pathogenesis of diabetic kidney diseases between genders.

Sexual Dimorphism of NAFLD in Adults. Focus on Clinical Aspects and Implications for Practice and Translational Research

Nonalcoholic fatty liver disease (NAFLD) embraces the clinico-pathological consequences of hepatic lipotoxicity and is a major public health problem globally. Sexual dimorphism is a definite feature of most human diseases but, under this aspect, NAFLD lags behind other medical fields. Here, we aim at summarizing and critically discussing the most prominent sex differences and gaps in NAFLD in humans, with emphasis on those aspects which are relevant for clinical practice and translational research. Sexual dimorphism of NAFLD is covered with references to the following areas: disease prevalence and risk factors, pathophysiology, comorbidities, natural course and complications. Finally, we also discuss selected gender differences and whether sex-specific lifestyle changes should be adopted to contrast NAFLD in men and women.

Biochemical and Hematological Correlates of Elevated Homocysteine in National Surveys and a Longitudinal Study of Urban Adults

Elevated blood homocysteine (Hcy) among middle-aged adults can increase age-related disease risk, possibly through other biochemical and hematological markers. We selected markers for hyperhomocysteinemia among middle-aged adults, studied time-dependent Hcy-marker associations and computed highly predictive indices of hyperhomocysteinemia, with cross-sectional and longitudinal validations. We used data from the National Health and Nutrition Examination Survey (NHANES III, phase 2, n_max = 4000), the NHANES 1999–2006 (n_max = 10,151) and pooled NHANES (cross-sectional validation). Longitudinal validation consisted of mixed-effects linear regression models (Hcy predicting markers’ annual rates of change), applied to the Healthy Aging in Neighborhoods of Diversity Across the Life Span (HANDLS, n = 227–244 participants, k = 2.4 repeats/participant, Age_base: 30–65 years) data. Machine learning detected nine independent markers for Hcy > 14 µmol/L (NHANES III, phase 2): older age; lower folate and B-12 status; higher serum levels of creatinine, uric acid, alkaline phosphatase, and cotinine; mean cell hemoglobin and red cell distribution widths (RDW); results replicated in the 1999–2006 NHANES [AUC = 0.60–0.80]. Indices combining binary markers increased elevated Hcy odds by 6.9–7.5-fold. In HANDLS, first-visit Hcy predicted annual increase in creatinine, RDW and alkaline phosphatase, with third-visit index (2013–2018) directly predicting Hcy (2004–2009). We provide evidence of the internal and external validity of indices composed of several biomarkers that are strongly associated with elevated Hcy.

One-carbon metabolism gene polymorphisms are associated with cognitive trajectory among African-American adults

The sex-specific link between longitudinal annual rate of cognitive change (LARCC) and polymorphisms in one-carbon metabolism enzymatic genes remains unclear, particularly among African-American adults. We tested associations of 14 single nucleotide polymorphisms (SNPs) from MTHFR, MTRR, MTR, and SHMT genes and select MTHFR haplotypes and latent classes (SNPHAP/SNPLC) with LARCC. Up to 797 African-American participants in the Healthy Aging in Neighborhoods of Diversity across the Life Span study (age: 30-64 y, 52% women) had 1.6-1.7 (i.e., 1 or 2) repeated measures (follow-up time, mean = 4.69 y) on 9 cognitive test scores, reflecting verbal and visual memory, verbal fluency, psychomotor speed, attention, and executive function: California Verbal Learning Test-immediate recall (CVLT-List A), CVLT-DFR (delayed free recall), Benton Visual Retention Test (BVRT), Animal Fluency (AF), Digits Span Forward and Backward tests, and Trail Making Test parts A and B (Trails A and B). Multiple linear mixed-effects and multiple linear regression models were conducted. Overall, MTHFR SNPs rs4846051(A1317G, G>A) and rs1801131(A1298C, G>T) were associated with slower and faster declines on AF, respectively, whereas rs2066462(C1056T, A>G) was related to slower decline on Trails B (executive function). Among men, rs4846051(A1317G, G>A) was linked to faster decline on BVRT (visual memory), whereas rs2066462(C1056T, A>G) and rs9651118(C>T) were associated with slower decline on CVLT-List A and rs9651118(C>T) with faster decline on CVLT-DFR. Among women, a slower decline on the domain "verbal memory/fluency" was observed with rs1801133(C677T, A>G). MTHFR₂SNPHAP [rs1801133(C677T, A>G)/rs1801131(A1298C, G>T): GG] was associated with slower decline on AF among women, whereas MTHFR₃SNPHAP(AT) was linked with slower decline on CVLT-List A among men but faster decline on "verbal memory/fluency" among women. Similar patterns were observed for MTHFR SNPLCs. In sum, MTHFR gene variations can differentially impact longitudinal changes in multiple cognitive domains among African-American adults.