Plasma Dimethylglycine Research Articles

Exposure to prenatal excess or imbalanced micronutrients leads to long-term perturbations in one-carbon metabolism, trimethylamine-N-oxide and DNA methylation in Wistar rat offspring.

Prenatal multivitamins, including folic acid, are commonly consumed in excess, whereas choline, an essential nutrient and an important source of labile methyl groups, is underconsumed. Here, we characterized profiles of one-carbon metabolism and related pathways andpatterns of DNA methylation in offspring exposed to excess or imbalanced micronutrients prenatally. Pregnant Wistar rats were fed either recommended 1× vitamins (RV), high 10× vitamins (HV), high 10× folic acid with recommended choline (HFolRC), or high 10× folic acid with no choline (HFolNC). Offspring were weaned to a high-fat diet for 12 weeks. Circulating metabolites were analyzed with a focus on the hypothalamus, an area known to be under epigenetic regulation. HV, HFolRC, and HFolNC males had higher body weight (BW) and lower plasma choline and methionine consistent with lower hypothalamic S-adenosylmethionine (SAM):S-adenosylhomocysteine (SAH) and global DNA methylation compared with RV. HV and HFolNC females had higher BW and lower plasma 5-methyltetrahydrofolate and methionine consistent with lower hypothalamic global DNA methylation compared with RV. Plasma dimethylglycine (DMG) and methionine were higher as with hypothalamic SAM:SAH and global DNA methylation in HFolRC females without changes in BW compared with RV. Plasma trimethylamine and trimethylamine-N-oxide were higher in males but lower in females from HFolRC compared with RV. Network modeling revealed a link between the folate-dependent pathway and SAH, with most connections through DMG. Final BW was negatively correlated with choline, DMG, and global DNA methylation. In conclusion, prenatal intake of excess or imbalanced micronutrients induces distinct metabolic and epigenetic perturbations in offspring that reflect long-term nutritional programming of health.

Relationship between one-carbon metabolism and fetal growth in twins: A cohort study.

We investigated the associations of one-carbon metabolism (OCM)-related metabolites, including choline, betaine, dimethylglycine (DMG), and methionine with fetal growth of twins. This hospital-based cohort study included dichorionic twin gestations. Blood samples were collected at a median of 14.7 weeks of gestation. Blood plasma metabolite levels were measured using high-performance liquid chromatography-triple quadrupole mass spectrometry. Generalized estimating equations and mixed effects models were used to explore associations between plasma metabolite levels and fetal growth. In total, 115 women with dichorionic diamniotic pregnancies were included. The maternal plasma DMG level was negatively correlated with fetal birth weight (β = -43.5, 95% confidence interval [CI] = -74.1 to -12.8, p < .05) and head circumference (β = -0.23, 95% CI = -0.39 to -0.07, p < .05). Other metabolites were not significantly associated with birth weight, body length, head circumference (HC), or chest circumference. Analysis of the relationships between plasma metabolite levels and fetal biological parameters on ultrasound revealed that the maternal choline level was negatively correlated with fetal abdominal circumference (AC) (β = -0.12, 95% CI = 0.24 to -0.004, p < .05); the maternal DMG level was negatively correlated with fetal AC (β = -0.17, 95% CI = 0.28-0.07, p < .05), femur length (β = 0.02, 95% CI = 0.04-0.003, p < .05), and estimated fetal weight (β = 26.4, 95% CI = -41.6 to -11.2, p < .05), but not with HC. The maternal methionine level was negatively correlated with HC (β = -0.08, 95% CI = -0.14 to -0.02, p < .05). The plasma level of the OCM-related metabolite DMG during the second trimester was negatively correlated with fetal intrauterine growth and birth weight. However, further studies with larger samples are needed.

Children Aged 5–6 Years in Vancouver, Canada Meet Dietary Recommendations for Folate and Vitamin B12 but not Choline

BackgroundCholine, folate, and vitamin B12 are required for growth and development, but there is limited information on the intakes and relationships to biomarkers of status in children. ObjectivesThe objective of this study was to determine the choline and B-vitamin intakes and relationship to biomarkers of status in children. MethodsA cross-sectional study was conducted in children (n = 285, aged 5–6 y) recruited from Metro Vancouver, Canada. Dietary information was collected by using 3 24-h recalls. Nutrient intakes were estimated by using the Canadian Nutrient File and United States Department of Agriculture database for choline. Supplement information was collected by using questionnaires. Plasma biomarkers were quantified by using mass spectrometry and commercial immunoassays, and relationships to dietary and supplement intake were determined by using linear models. ResultsDaily dietary intakes of choline, folate, and vitamin B12 were [mean (SD)] 249 (94.3) mg, 330 (120) DFE μg, and 3.60 (1.54) μg, respectively. Top food sources of choline and vitamin B12 were dairy, meats, and eggs (63%–84%) and for folate, were grains, fruits, and vegetables (67%). More than half of the children (60%) were consuming a supplement containing B-vitamins, but not choline. Only 40% of children met the choline adequate intake (AI) recommendation for North America (≥250 mg/d); 82% met the European AI (≥170 mg/d). Less than 3% of children had inadequate folate and vitamin B12 total intakes. Some children (5%) had total folic acid intakes above the North American tolerable upper intake level (UL; >400 μg/d); 10% had intakes above the European UL (>300 μg/d). Dietary choline intake was positively associated with plasma dimethylglycine, and total vitamin B12 intake was positively associated with plasma B12 (adjusted models; P < 0.001). ConclusionsThese findings suggest that many children are not meeting the dietary choline recommendations, and some children may have excessive folic acid intakes. The impact of imbalanced one-carbon nutrient intakes during this active period of growth and development requires further investigation.

Intrauterine Growth-Restricted Piglets Are Predisposed to Develop Metabolic Disorders in Adulthood When Fed With Parenteral Nutrition in the Neonatal Period

ObjectivesTotal parenteral nutrition (TPN) is lifesaving yet non-normal nutrition regimen during the neonatal period. However, studies have shown that TPN feeding early in life can permanently alter metabolism at later ages. Moreover, intrauterine growth restricted (IUGR) neonates also have a higher risk of developing metabolic diseases (such as obesity and dyslipidemia) in later life. Because a substantial proportion of IUGR neonates receive TPN in early life, we wondered if the metabolic effects of feeding TPN early in life would exacerbate these effects of IUGR? We hypothesized that feeding TPN to IUGR neonates would aggravate the risk of developing obesity and dyslipidemia in adulthood.MethodsSixteen normal weight female piglets (7 d old) were randomized to sow-fed (SF) or early TPN (TPN-CON); 8 (IUGR or runt) piglets were fed TPN as a third group (TPN-IUGR). After 2 weeks of TPN or suckling, all pigs were fed a normal grower diet for 8 mo. At 8 mo, catheters were implanted and in vivo metabolic tests were conducted.ResultsTPN-IUGR pigs demonstrated catch-up growth by 4 mo, and body weights were not different among groups at 8 mo. The metabolic effects of feeding TPN persisted into adulthood, as indicated by higher postprandial plasma triglycerides (TG) and fasting plasma non-esterified fatty acids (NEFA), compared to SF (P < 0.05). IUGR exacerbated TPN-induced risk for diseases by worsening obesity outcomes with greater subcutaneous fat deposition (P < 0.05) and greater ectopic TG deposition in the liver (P < 0.05) and muscle (P < 0.05). Furthermore, IUGR led to dyslipidemia as indicated by higher cholesterol in fasted plasma LDL (P < 0.05), slower postprandial TG clearance (P < 0.05), higher fasting plasma NEFA (P < 0.001) and higher plasma dimethylglycine (P < 0.05), compared to the TPN-CON. IUGR pigs had greater VLDL secretion, as suggested by higher microsomal transfer protein mRNA (P < 0.05). Early TPN programmed reduced lipogenesis, as indicated by lower fatty acid synthase mRNA (P < 0.05), compared to SF.ConclusionsCollectively, these findings conclude that although TPN is a lifesaving measure, feeding TPN to IUGR neonates has long-term metabolic consequences predisposing them to develop metabolic disorders in adulthood.Funding SourcesCanadian Institutes of Health Research.

School-Aged Children in Vancouver, Canada Do Not Meet Dietary Choline Recommendations but Meet Recommendations for Folate and Vitamin B12

ObjectivesNutrients such as choline, betaine, folate, and vitamin B12 are required for proper growth and development, but little is known about these nutrients in children. Our objective was to determine intakes and biomarkers of these nutrients in school-aged children (5 to 6 years old). MethodsA cross-sectional study of healthy children (n = 285) recruited from Vancouver, Canada were assessed. Dietary information was collected using three 24-hour recalls. Nutrient intakes were estimated using the Canadian Nutrient File and USDA database for choline; supplement use was collected by questionnaire. Plasma biomarkers were quantified by mass spectrometry and immunoassay. ResultsDaily dietary intakes were (mean ± SD) choline 250 ± 96 mg, betaine 88 ± 41 mg, folate 335 ± 126 μg DFE, and vitamin B12 3.78 ± 2.71 μg. Top food sources were dairy and eggs (42–57%) for choline and vitamin B12, and cereal and grains (41–60%) for betaine and folate. Only 40% of children met the choline adequate intake (AI) recommendation for North America (≥250 mg/d); 81.5% met the European AI (≥170 mg/d). Plasma free choline, betaine, and dimethylglycine concentrations were (mean ± SD) 8.62 ± 2.13 μmol/L, 45.3 ± 13.7 μmol/L, 3.34 ± 1.03 μmol/L, respectively. Dietary choline intake and plasma free choline were not related. However, dietary choline intake was positively associated with plasma dimethylglycine. Less than 5% of children had inadequate folate and vitamin B12 intakes. More than half of the children (59.4%) were consuming a supplement containing B-vitamins, but none included choline or betaine. Some children (5.26%) had total folic acid intakes above the North American upper limit (UL; >400 μg/d); 10.90% had intakes above the European UL (>300 μg/d). Vitamin B12 intake was positively associated with plasma total vitamin B12 (mean ± SD; 594 ± 158 pmol/L) in an adjusted model (sex, age, total energy intake, and supplement use; p < 0.05). ConclusionsOur findings suggest that many school-aged children are not meeting dietary choline recommendations. Some children may have excessive folic acid intakes. The impact of imbalanced methyl nutrient intakes during this active period of growth and development needs to be determined in the future. Funding SourcesCIHR, NSERC, and BC Children’s Hospital Research Institute.

The expression levels of plasma dimethylglycine (DMG), human maternally expressed gene 3 (MEG3), and Apelin-12 in patients with acute myocardial infarction and their clinical significance.

To analyze the expression levels of plasma dimethylglycine (DMG), human maternally expressed gene 3 (MEG3), and Apelin-12 in patients with acute myocardial infarction (AMI) and explore their clinical significance. One hundred and ten patients with suspected AMI (chest pain duration <6 h) who were admitted to our hospital between December 2018 and June 2020 were included. Plasma DMG, MEG3, and Apelin-12 levels were measured at the time of admission. The levels of plasma DMG, MEG3, and Apelin-12, as well as the general data and admission baseline data of these patients were then compared with those of non-AMI patients. The receiver operating characteristic (ROC) curve was used to analyze the clinical value of plasma DMG, MEG3, and Apelin-12 levels for the early diagnosis of AMI. Among the 110 patients with chest pain suspected of AMI, 34 were clinically diagnosed with AMI, and 76 were non-AMI patients. The proportion of males, smoking, history of myocardial infarction, and congestive heart failure in the AMI group were higher than those of the non-AMI group. The proportions of systolic blood pressure (SBP), ST-segment elevation, and electrocardiogram (ECG) dynamic changes on admission were also higher in the AMI group compared to those of the non-AMI group (P<0.05). The plasma DMG, MEG3, and Apelin-12 levels of patients in the AMI group on admission were higher than those of the non-AMI group (P<0.05); all have diagnostic value for AMI upon admission. The area under the curve (AUC) of MEG3 was higher than that of both DMG and Apelin-12, however the difference was not statistically significant (Z=1.378, 0.934, P=0.168, 0.350). Using 0.015 as the cut-off value for MEG3-messenger ribonucleic acid (mRNA), the sensitivity and specificity for diagnosing AMI were 85.29% and 81.58%, respectively. Our results showed that the plasma levels of DMG, MEG3, and Apelin-12 in patients with AMI were high, and thus, they can be used as biomarkers for the early diagnosis of AMI. Among them, MEG3 was the most effective in early diagnosing AMI.

Short communication: Effects of dietary deoiled soy lecithin supplementation on circulating choline and choline metabolites, and the plasma phospholipid profile in Holstein cows fed palm fat

Dietary lecithin is a source of choline. Our objective was to evaluate the effects of dietary deoiled soy lecithin feeding on circulating choline, choline metabolites, and the plasma phospholipid profile in lactating dairy cows fed fractionated palm fatty acids. In a split-plot Latin square design, 16 Holstein cows (160 ± 7 d in milk; 3.6 ± 1.2 parity) were randomly allocated to a main plot receiving a corn silage and alfalfa haylage-based diet with palm fat containing either moderate or high palmitic acid content at 1.75% of ration dry matter (moderate and high palmitic acid containing 72 or 99% palmitic acid in fat supplement, respectively; n = 8/palm fat diet). Within each palm fat group, deoiled soy lecithin was top-dressed at 0, 0.12, 0.24, or 0.36% of ration dry matter in a replicated 4 × 4 Latin square design with 14-d experimental periods. A 14-d covariate period was used to acclimate cows to palm fat feeding without lecithin supplementation. Blood sampling occurred during the final 3 d of each experimental period. Plasma choline and choline metabolites were quantified using liquid chromatography and mass spectrometry. Plasma phospholipids were profiled using time-of-flight mass spectrometry. Whereas no effects of treatments were detected for plasma choline or methionine, lecithin feeding increased the plasma concentrations of choline metabolites trimethylamine N-oxide and dimethylglycine (24 and 11%, respectively). Plasma phosphatidylcholine (PC) and sphingomyelin (SM) concentrations increased with deoiled lecithin feeding (e.g., PC 16:0/22:6 and SM d18:1/18:3). Lecithin supplementation also increased plasma lysophosphatidylcholine (LPC) concentrations (e.g., LPC 18:0) while reducing plasma phosphatidylethanolamine (PE) concentrations (e.g., PE 16:0/20:5). Although increases in microbial-derived trimethylamine N-oxide suggest gastrointestinal lecithin degradation, elevations in plasma dimethylglycine, PC, LPC, and SM suggest that choline availability was improved by lecithin feeding in cows, thus supporting enhanced endogenous phospholipid synthesis.

Associations between Plasma Choline Metabolites and Genetic Polymorphisms in One-Carbon Metabolism in Postmenopausal Women: The Women's Health Initiative Observational Study

Background:Choline plays an integral role in one-carbon metabolism in the body, but it is unclear whether genetic polymorphisms are associated with variations in plasma choline and its metabolites. Objectives:This study aimed to evaluate the association of genetic variants in choline and one-carbon metabolism with plasma choline and its metabolites. Methods:We analyzed data from 1423 postmenopausal women in a case-control study nested within the Women's Health Initiative Observational Study. Plasma concentrations of choline, betaine, dimethylglycine (DMG), and trimethylamine N-oxide were determined in 12-h fasting blood samples collected at baseline (1993–1998). Candidate and tagging single-nucleotide polymorphisms (SNPs) were genotyped in betaine-homocysteine S-methyltransferase (BHMT), BHMT2, 5,10-methylenetetrahydrofolate reductase (MTHFR), methylenetetrahydrofolate dehydrogenase (NADP+ dependent 1) (MTHFD1), 5-methyltetrahydrofolate-homocysteine methyltransferase (MTR), and 5-methyltetrahydrofolate-homocysteine methyltransferase reductase (MTRR). Linear regression was used to derive percentage difference in plasma concentrations per variant allele, adjusting for confounders, including B-vitamin biomarkers. Potential effect modification by plasma vitamin B-12, vitamin B-6, and folate concentrations and folic-acid fortification periods was examined. ResultsThe candidate SNP BHMT R239Q (rs3733890) was associated with lower concentrations of plasma betaine and DMG concentrations (–4.00% and –6.75% per variant allele, respectively; both nominal P < 0.05). Another candidate SNP, BHMT2 rs626105 A>G, was associated with higher plasma DMG concentration (13.0%; P < 0.0001). Several tagSNPs in these 2 genes were associated with plasma concentrations after correction for multiple comparisons. Vitamin B-12 status was a significant effect modifier of the association between the genetic variant BHMT2 rs626105 A>G and plasma DMG concentration. ConclusionsGenetic variations in metabolic enzymes were associated with plasma concentrations of choline and its metabolites. Our findings contribute to the knowledge on the variation in blood nutrient concentrations in postmenopausal women.

P1531The association between plasma choline and acute myocardial infarction is modified by potential markers of endogenous PPAR activation

Abstract Background Choline is related to lipid handling and higher plasma concentrations have been associated with an adverse cardiovascular risk profile. However, previous studies have suggested that the relationship between plasma free choline and later cardiovascular events may differ according to patient phenotypes. Purpose To explore the risk association between plasma choline and later acute myocardial infarction (AMI) according to plasma methylmalonic acid (MMA) or dimethylglycine (DMG). The latter two metabolites are suggested markers of endogenous activation of perixosome proliferator-activated receptors (PPARs), which are nuclear receptor proteins involved in lipid metabolism. Methods Risk relationships were explored by Cox regression among 2232 patients evaluated for suspected stable angina pectoris in the overall population and according to median plasma MMA and DMG. Results Baseline plasma choline was related to several cardiovascular risk factors (Table 1). After median follow-up of 7.3 years, 338 patients were reported with at least one incident AMI. In the overall population, the age and gender adjusted HR (95% CI) for each increment of 1 SD log-transformed plasma choline and AMI was 1.21 (1.08–1.35), P=0.001, and the association persisted in multivariate analyses. In patients with plasma MMA or DMG≥median, the HRs (95% CIs) were 1.33 (1.16–1.54) and 1.38 (1.20–1.58), respectively, both P&lt;0.0001; however no significant relationships were observed between plasma choline and later AMI among patients with either plasma MMA or DMG &lt; median (P interaction &lt;0.008) (Figure 1). &lt;MEDIAN (P&gt; Table 1. Baseline characteristics according to plasma choline quartiles Quartile 1 Quartile 4 P for trend Age, years 58 (52–66) 66 (58–73) &lt;0.0001 Smoking, n (%) 212 (37.9) 153 (27.9) &lt;0.0001 Diabetes, n (%) 61 (10.9) 85 (15.5) 0.12 Previous acute myocardial infarction, n (%) 200 (35.7) 238 (43.4) &lt;0.0001 Estimated glomerular filtration rate, mL/min/1.73m2 96 (87–104) 79 (63–92) &lt;0.0001 Serum hs-troponin T, ng/L 4 (3–8) 9 (4–17) 0.0002 Serum triglycerides, mmol/L 1.35 (1.00–2.03) 1.60 (1.16–2.25) &lt;0.0001 Serum apolipoprotein A1, mg/L 1.29 (1.12–1.51) 1.32 (1.17–1.53) 0.01 Statin therapy, n (%) 384 (68.6) 435 (79.4) 0.01 Figure 1 Conclusion Among patients with stable angina, plasma choline was related to increased long-term AMI risk among patients with higher plasma MMA or DMG only. This finding potentially reflects increased risk conferred by choline during concomitant endogenous PPAR activation. Acknowledgement/Funding None

Plasma choline, homocysteine and vitamin status in healthy adults supplemented with krill oil: a pilot study

Plasma concentrations of metabolites along the choline oxidation and tryptophan degradation pathways have been linked to lifestyle diseases and dietary habits. This study aimed to investigate how krill oil, a source of ω-3 polyunsaturated fatty acids (PUFAs) with a high phosphatidylcholine content, affected these parameters. The pilot study was conducted as a 28 days intervention in 17 healthy volunteers (18–36 years), who received a supplement of 4.5 g krill oil per day, providing 833 mg ω-3 PUFAs, and 1750 mg phosphatidylcholine. Krill oil supplementation increased fasting plasma choline (+28.4%, p < .001), betaine (+26.6%, p < .001), dimethylglycine (+33.7%, p < .001) and sarcosine (+16.8%, p < .001), whereas no statistically significant changes were seen for plasma glycine, serine, methionine, total homocysteine, cysteine, cystathionine, methionine sulfoxide, folate, cobalamin, B2-, B3-, and B6 vitamers, tryptophan, kynurenines, nicotinamide, vitamin A and vitamin E. In summary, krill oil supplementation influenced choline metabolite levels, but not plasma metabolites of the tryptophan-kynurenine-nicotinamide pathways and vitamins. These observations should be confirmed in a placebo-controlled trial, including an ω-3 PUFA supplement without phospholipids to explore the potential additive effects of the different active ingredients.

Metabolic Effects of Betaine: A Randomized Clinical Trial of Betaine Supplementation in Prediabetes.

Plasma betaine correlates with insulin sensitivity in humans. Betaine supplementation improves metabolic effects in mice fed a high-fat diet. To assess metabolic effects of oral betaine in obese participants with prediabetes. A 12-week, parallel arm, randomized, double-masked, placebo-controlled trial. University-affiliated hospital. Persons with obesity and prediabetes (N = 27) were randomly assigned to receive betaine 3300 mg orally twice daily for 10 days, then 4950 mg twice daily for 12 weeks, or placebo. Changes from baseline in insulin sensitivity, glycemia, hepatic fat, and endothelial function. There was a 16.5-fold increase in plasma dimethylglycine [dimethylglycine (DMG); P < 0.0001] levels, but modest 1.3- and 1.5-fold increases in downstream serine and methionine levels, respectively, in the betaine vs placebo arm. Betaine tended to reduce fasting glucose levels (P = 0.08 vs placebo) but had no other effect on glycemia. Insulin area under curve after oral glucose was reduced for betaine treatment compared with placebo (P = 0.038). Insulin sensitivity, assessed by euglycemic hyperinsulinemic clamp, was not improved. Serum total cholesterol levels increased after betaine treatment compared with placebo (P = 0.032). There were no differences in change in intrahepatic triglyceride or endothelial function between groups. DMG accumulation supports DMG dehydrogenase as rate limiting for betaine metabolism in persons with prediabetes. Betaine had little metabolic effect. Additional studies may elucidate mechanisms contributing to differences between preclinical and human responses to betaine, and whether supplementation of metabolites downstream of DMG improves metabolism.

Maternal Folate Status and the BHMT c.716G>A Polymorphism Affect the Betaine Dimethylglycine Pathway during Pregnancy.

The effect of the betaine: homocysteine methyltransferase BHMT c.716G>A (G: guanosine; A: adenosine) single nucleotide polymorphism (SNP) on the BHMT pathway is unknown during pregnancy. We hypothesised that it impairs betaine to dimethylglycine conversion and that folate status modifies its effect. We studied 612 women from the Reus Tarragona Birth Cohort from ≤12 gestational weeks (GW) throughout pregnancy. The frequency of the variant BHMT c.716A allele was 30.8% (95% confidence interval (CI): 28.3, 33.5). In participants with normal-high plasma folate status (>13.4 nmol/L), least square geometric mean [95% CI] plasma dimethylglycine (pDMG, µmol/L) was lower in the GA (2.35 [2.23, 2.47]) versus GG (2.58 [2.46, 2.70]) genotype at ≤12 GW (p < 0.05) and in the GA (2.08 [1.97, 2.19]) and AA (1.94 [1.75, 2.16]) versus GG (2.29 [2.18, 2.40]) genotypes at 15 GW (p < 0.05). No differences in pDMG between genotypes were observed in participants with possible folate deficiency (≤13.4 nmol/L) (p for interactions at ≤12 GW: 0.023 and 15 GW: 0.038). PDMG was lower in participants with the AA versus GG genotype at 34 GW (2.01 [1.79, 2.25] versus 2.44 [2.16, 2.76] and at labour, 2.51 [2.39, 2.64] versus 3.00 [2.84, 3.18], (p < 0.01)). Possible deficiency compared to normal-high folate status was associated with higher pDMG in multiple linear regression analysis (β coefficients [SEM] ranging from 0.07 [0.04], p < 0.05 to 0.20 [0.04], p < 0.001 in models from early and mid-late pregnancy) and the AA compared to GG genotype was associated with lower pDMG (β coefficients [SEM] ranging from −0.11 [0.06], p = 0.055 to −0.23 [0.06], p < 0.001). Conclusion: During pregnancy, the BHMT pathway is affected by folate status and by the variant BHMT c.716A allele.

Supplementation with Folic Acid, but Not Creatine, Increases Plasma Betaine, Decreases Plasma Dimethylglycine, and Prevents a Decrease in Plasma Choline in Arsenic-Exposed Bangladeshi Adults

Background: Folic acid (FA) supplementation facilitates urinary excretion of arsenic, a human carcinogen. A better understanding of interactions between one-carbon metabolism intermediates may improve the ability to design nutrition interventions that further facilitate arsenic excretion.Objective: The objective was to determine if FA and/or creatine supplementation increase choline and betaine and decrease dimethylglycine (DMG).Methods: We conducted a secondary analysis of the Folic Acid and Creatine Trial, a randomized trial in arsenic-exposed Bangladeshi adults (n = 605, aged 24–55 y, 50.3% male) who received arsenic-removal water filters. We examined treatment effects of FA and/or creatine supplementation on plasma choline, betaine, and DMG concentrations, measured by LC–tandem mass spectrometry at baseline and at week 12. Group comparisons were between 1) 400 and 800 μg FA/d (FA400 and FA800, respectively) compared with placebo, 2) creatine (3 g/d) compared with placebo, and 3) creatine plus FA400 compared with FA400.Results: Choline decreased in the placebo group (−6.6%; 95% CI: −10.2%, −2.9%) but did not change in the FA groups (FA400: 2.5%; 95% CI: −0.9%, 6.1%; FA800: 1.4%; 95% CI: −2.5%, 5.5%; P < 0.05). Betaine did not change in the placebo group (−3.5%; 95% CI: −9.3%, 2.6%) but increased in the FA groups (FA400: 14.1%; 95% CI: 9.4%, 19.0%; FA800: 13.0%; 95% CI: 7.2%, 19.1%; P < 0.01). The decrease in DMG was greater in the FA groups (FA400: −26.7%; 95% CI: −30.9%, −22.2%; FA800: −27.8%; 95% CI: −31.8%, −23.4%) than in the placebo group (−12.3%; 95% CI: −18.1%, −6.2%; P < 0.01). The percentage change in choline, betaine, and DMG did not differ between creatine treatment arms and their respective reference groups.Conclusion: Supplementation for 12 wk with FA, but not creatine, increases plasma betaine, decreases plasma DMG, and prevents a decrease in plasma choline in arsenic-exposed Bangladeshi adults. This trial was registered at clinicaltrials.gov as NCT01050556.

Dimethylglycine Deficiency and the Development of Diabetes.

Experimental studies have suggested possible protective effects of dimethylglycine (DMG) on glucose metabolism. DMG is degraded to glycine through a DMG-dehydrogenase (DMGDH)-catalyzed reaction, and this is the only known pathway for the breakdown of DMG in mammals. In this study, we aimed to identify the strongest genetic determinant of circulating DMG concentration and to investigate its associations with metabolic traits and incident diabetes. In the cohort with full metabolomics data (n = 709), low plasma levels of DMG were significantly associated with higher blood glucose levels (P = 3.9E–4). In the genome-wide association study (GWAS) of the discovery cohort (n = 5,205), the strongest genetic signal of plasma DMG was conferred by rs2431332 at the DMGDH locus, where the major allele was associated with lower DMG levels (P = 2.5E–15). The same genetic variant (major allele of rs2431332) was also significantly associated with higher plasma insulin (P = 0.019), increased HOMA insulin resistance (P = 0.019), and an increased risk of incident diabetes (P = 0.001) in the pooled analysis of the discovery cohort together with the two replication cohorts (n = 20,698 and n = 7,995). These data are consistent with a possible causal role of DMG deficiency in diabetes development and encourage future studies examining if inhibition of DMGDH, or alternatively, supplementation of DMG, might prove useful for the treatment/prevention of diabetes.

Plasma dimethylglycine, nicotine exposure and risk of low bone mineral density and hip fracture: the Hordaland Health Study.

In the large community-based Hordaland Health Study, low plasma dimethylglycine was associated with low bone mineral density in both middle-aged and elderly subjects and to an increased risk of subsequent hip fracture among the elderly. These associations seemed to be particularly strong among subjects exposed to nicotine. Dimethylglycine (DMG) is a product of the choline oxidation pathway and formed from betaine during the folate-independent remethylation of homocysteine (Hcy) to methionine. Elevated plasma DMG levels are associated with atherosclerotic cardiovascular disease and inflammation, which in turn are related to osteoporosis. High plasma total Hcy and low plasma choline are associated with low bone mineral density (BMD) and hip fractures, but the role of plasma DMG in bone health is unknown. We studied the associations of plasma DMG with BMD among 5315 participants (46-49 and 71-74 years old) and with hip fracture among 3310 participants (71-74 years old) enrolled in the Hordaland Health Study. In age and sex-adjusted logistic regression models, subjects in the lowest versus highest DMG tertile were more likely to have low BMD (odds ratio [OR] 1.68, 95% confidence interval [CI] 1.43-1.99). The association was stronger in participants exposed compared to those unexposed to nicotine (OR 2.31, 95% CI 1.73-3.07 and OR 1.43, 95% CI 1.16-1.75, respectively, p interaction = 0.008). In the older cohort, Cox regression analyses adjusted for sex showed that low plasma DMG was associated with an increased risk of hip fracture (hazard ratio [HR] 1.70, 95% CI 1.28-2.26). A trend toward an even higher risk was found among women exposed to nicotine (HR 3.41, 95% CI 1.40-8.28). Low plasma DMG was associated with low BMD and increased risk of hip fractures. A potential effect modification by nicotine exposure merits particular attention.

Plasma methionine, choline, betaine, and dimethylglycine in relation to colorectal cancer risk in the European Prospective Investigation into Cancer and Nutrition (EPIC)

Disturbances in one carbon metabolism may contribute to carcinogenesis by affecting methylation and synthesis of DNA. Choline and its oxidation product betaine are involved in this metabolism and can serve as alternative methyl group donors when folate status is low. We conducted a case-control study nested within the European Prospective Investigation into Cancer and Nutrition (EPIC), to investigate plasma concentrations of the methyl donors methionine, choline, betaine (trimethylglycine), and dimethylglycine (DMG) in relation to colorectal cancer (CRC) risk. Our study included 1367 incident CRC cases (965 colon and 402 rectum) and 2323 controls matched by gender, age group, and study center. Multivariate-adjusted odds ratios (ORs) and 95% confidence intervals (95% CIs) for CRC risk were estimated by conditional logistic regression, comparing the fifth to the first quintile of plasma concentrations. Overall, methionine (OR: 0.79, 95% CI: 0.63-0.99, P-trend = 0.05), choline (OR: 0.77, 95% CI: 0.60-0.99, P-trend = 0.07), and betaine (OR: 0.85, 95% CI: 0.66-1.09, P-trend = 0.06) concentrations were inversely associated with CRC risk of borderline significance. In participants with folate concentration below the median of 11.3 nmol/l, high betaine concentration was associated with reduced CRC risk (OR: 0.71, 95% CI: 0.50-1.00, P-trend = 0.02), which was not observed for those having a higher folate status. Among women, but not men, high choline concentration was associated with decreased CRC risk (OR: 0.62, 95% CI: 0.43-0.88, P-trend = 0.01). Plasma DMG was not associated with CRC risk. Individuals with high plasma concentrations of methionine, choline, and betaine may be at reduced risk of CRC.

Elevated plasma dimethylglycine is a risk marker of mortality in patients with coronary heart disease

To investigate whether plasma dimethylglycine was associated with and improved risk prediction of mortality among patients with coronary heart disease (CHD). By Cox modelling, we explored the association between plasma dimethylglycine and mortality in two independent cohorts of patients with suspected stable angina pectoris (SAP) (n = 4156) and acute myocardial infarction (AMI) (n = 3733). We also assessed any improvement in risk prediction by adding plasma dimethylglycine to established CHD risk factors. Median follow-up time was 4.7 and 7.0 years among patients with SAP and AMI, respectively. Across both cohorts, elevated plasma dimethylglycine levels were linearly associated with increased risk of all-cause mortality (age and gender adjusted hazard ratios (95% confidence interval, CI) were 1.72 (1.21-2.46) and 1.76 (1.42-2.18) when comparing the fourth versus the first plasma dimethylglycine quartile in patients with SAP and AMI, respectively). There was a particularly strong risk association between plasma dimethylglycine and cardiovascular, as compared with non-cardiovascular, mortality (age and gender adjusted hazard ratios (95% CI) 1.94 (1.21-3.11) and 1.43 (0.83-2.47) among patients with SAP and 1.97 (1.50-2.59) and 1.44 (1.02-2.04) among patients with AMI, respectively). The relationship between dimethylglycine and all-cause and cardiovascular mortality was only slightly attenuated in analyses adjusted for established CHD risk factors. Plasma dimethylglycine also improved risk prediction for all-cause and cardiovascular mortality, and especially among patients with AMI. Elevated plasma dimethylglycine was associated with and improved risk prediction of mortality in patients with suspected or verified CHD. This relationship was stronger for death from cardiovascular, as compared with non-cardiovascular, causes.

Abstract P452: Pathway Analysis Of One-carbon Metabolism In Association With Acute Myocardial Infarction In Patients With Stable Angina Pectoris

Background: One-carbon metabolism (OCM) is involved in RNA, DNA synthesis and in epigenetic regulation. Pathway gene analysis is more likely to capture potential gene-disease associations comparing to single gene analysis. We investigated whether genetic variants in folate network as well as their interactions would predict subsequent acute myocardial infarction (AMI) in patients undergoing elective coronary angiography for stable angina pectoris (SAP). Methods: A total of 2381 subjects (98% Caucasian) recruited to the Western Norway B Vitamin Intervention Trial (WENBIT) in 2000-2004 were studied. Patients were followed until a subsequent AMI or end of 2006. We genotyped 18 commonly investigated single nucleotide polymorphisms (SNPs) in 13 genes in the OCM network. Predictable variants were selected based on both out-of-bag importance scores from random survival forests and their incremental effects from recursive nested analysis. We then assessed gene-gene interactions among those predictive variants with generalized logistic model and calculated hazard ratio (HR), confidence interval (CI) for each predictor in Cox proportional hazard models. Results: There are 204 (8.57%) patients who experienced an AMI throughout 4.9 years (median) follow-up. We observed no violation from Hardy-Weinberg equilibrium in 15 SNPs in our population. Four SNPs (rs1076991, rs1021737, rs1801133 and rs3733890) in folate network were identified as promising candidates for predicting AMI risk. Interestingly, only rs1076991 associated significantly with AMI (HR=1.30, 95% CI: 1.10-1.52), indicating the other SNPs primarily mediate their risk bygene-gene interactions. There was a strong and stable interaction between the dominant model of rs3733890 and dominant model of rs34489327 (P for interaction: 0.003; HR =2.23, 95% CI: 1.27-3.92, adjusted for age, gender, smoking, diabetes mellitus, hypertension, extent of CAD by angiography (0-3), apolipoprotein (Apo) A1 and B, left ventricular ejection fraction and estimated glomerular filtration rate). Further adjustment for vitamins involved in OCM (folate, B2, B6, B12), the substrates (betaine and homocysteine) and products (methionine and dimethylglycine) of the betaine--homocysteine S-methyltransferase (BHMT) had minimal influence on the estimate. Conclusions: Prior studies show that BHMT transcription is associated with co-transcription of Apo B and that the rs3733890 of this gene is associated with higher dimethylglycine levels. We have recently shown that elevated plasma dimethylglycine is associated with increased risk of AMI and improves risk prediction in patients with SAP independent of Apo B levels. The current investigation extends previous knowledge, suggesting that a genetic variant in BHMT may modulate the risk of AMI by interfering with thymidylate synthesis independent of plasma dimethylglycine.

Plasma Dimethylglycine and Risk of Incident Acute Myocardial Infarction in Patients With Stable Angina Pectoris

Dimethylglycine is linked to lipid metabolism, and increased plasma levels may be associated with adverse prognosis in patients with coronary artery disease. We evaluated the relationship between plasma dimethylglycine and risk of incident acute myocardial infarction in a large prospective cohort of patients with stable angina pectoris, of whom approximately two thirds were participants in a B-vitamin intervention trial. Model discrimination and reclassification when adding plasma dimethylglycine to established risk factors were obtained. We also explored temporal changes and the test-retest reliability of plasma dimethylglycine. Four thousand one hundred fifty patients (72% men; median age 62 years) were included. Plasma dimethylglycine was associated with several traditional coronary artery disease risk factors. During a median follow-up of 4.6 years, 343 (8.3%) patients experienced an acute myocardial infarction. The hazard ratio (95% confidence interval) for acute myocardial infarction was 1.95 (1.42-2.68; P<0.001) when comparing plasma dimethylglycine quartile 4 to 1 in a Cox regression model adjusted for age, sex, and fasting status. Adjusting for traditional coronary artery disease risk factors only slightly modified the estimates, which were particularly strong among nonsmokers and among patients with serum triglyceride or apolipoprotein B100 levels ≤ median (P for interaction=0.004, 0.004, and 0.03, respectively). Plasma dimethylglycine improved discrimination and reclassification and had high test-retest reliability. Plasma dimethylglycine is independently related to incident acute myocardial infarction and enhances risk prediction in patients with stable angina pectoris. Our results motivate further studies on the relationship between 1-carbon metabolism and atherothrombosis. A potential interplay with lipid and energy metabolism merits particular attention.

Influence of lactation and choline intake on one‐carbon biomarkers in women

ObjectiveWe sought to quantify the effects of lactation and maternal choline intake on maternal indicators of one‐carbon metabolism.MethodsLactating (n = 28; 30‐d post‐partum) and nonlactating (NL, n = 21) women were randomized to choline intakes of 480 or 930 mg/d for 10 weeks. Blood and urine were collected at baseline, study midpoint, and study end for analysis of one carbon metabolites.ResultsCompared to NL women, lactating women exhibited elevated plasma choline (p=0.04) and decreased urinary dimethylglycine losses (p=0.008). Within lactating women, a higher choline intake yielded greater plasma betaine (p=0.015), greater plasma dimethylglycine (p=0.037), greater plasma methylglycine (p=0.036), and decreased plasma cystathionine (p=0.012). However, higher choline intake did not affect plasma concentrations of homocysteine, cysteine, methionine, or glycine.ConclusionsLactation and choline intake influence biomarkers of 1‐C metabolism with some evidence of a greater demand for choline during lactation and a positive effect of a higher choline intake on methyl group supply.