There were over 240 delegates to the 10th International Conference on One Carbon Metabolism, B Vitamins and Homocysteine at the Medical School at the University of Lorraine.

Whilst most of the subjects were way over my head (and over the heads of some of the professionals there) I have included below the titles of the papers presented and a short summary of the research.  Please don’t leave messages asking for further clarification – I am not scientifically qualified and won’t be able to answer you.

The title of the speaker is given and not all of the authors of the individual papers.

 

Session 1: Enzymes and co-enzymes of the one carbon metabolism: the mechanistic interplay and alternative reactions
Chairs: J.P. Kraus and W. Kruger

1.Lessons in biology from patients with inherited disorders of vitamin B12 metabolism; D. S. Rosenblatt, (Montreal, Canada)

“We have been able to define steps in intracellular cobalamin metabolism and to identify five novel complementation groups…and the first patients with a defect in the transcobalamin receptor.  In addition, we have described the first patient with mutations in the MTHFD1 Gene which is involved in the interconversion of folate coenzyme forms, resulting in the altered flux of single carbon units into thymidine, and severe combined immunodeficiency”.

2. CBS News; Structure, Regulation and Enzyme Replacement Therapy; J. P. Kraus (Aurora, USA)

CBS* upon SAM**binding undergoes a large structural movement of its regulatory regions to allow substrate access to the catalytic sites. Our results strongly suggest that CBS ERT*** is a viable alternative to the existing therapies for homocystinuria”.

*Cystathionine beta-synthase

**S-adenosylmethionine

***Enzyme Replacement Therapy

3.Promiscuity of enzymes in sulfur amino acid metabolism: hydrogen sulfide production in homocystinurias; V. Kozich (Prague, Czech Republic)

“This study implies that deficient CBS activity results in decreased H2S* production, which is in vivo compensated by enhanced synthesis of hydrogen sulfide from homocysteine by CTH**”

*Hydrogen Sulfide

**Cystothionase

4.  Investigations focused on the methionine synthase intercactome provide novel mechanistic insights about the intracellular metabolism of vitamin B12; D. Coelho (Nancy, France)

“…moreover our data suggest that a potential innovative treatment of patients with acquired or inherited disorders of Cbl metabolism could be based on SIRT1 agonists”

5.  Allosteric regulation of cystathionine beta-synthase and ligand-mediated stabilization of its regulatory domain; T Majtan (Aurora, United States).

“Results indicate that independent pharmacological targeting of regulatory and stabilizing sites in CBS may represent a feasible approach for development of CBS-specific kinetic stabilizers and thus rescue CBS activity”.
6. Visualization of a B12-dependentenzyme with its G-protein chaperone indicates molecular mechanisms of methylmalonic aciduria; M. Jost, D. Born (Cambridge, United States)
“The lcmF crystal structures reveal how G-protein chaperones associate with adenosylcobalamin-dependent enzymes to regulate cofactor delivery and indicate a molecular mechanism of pathogenicity for five methylmalonic adicuria-causing mutations”.
Session 2: Metabolic, molecular and cellular consequences of hyperhomocysteinemia and folate and vitamin B12 deficiencies
Chairs: J.L. Guéant and V. Kožich
1. Influence of folate deficiency on brain development and function: the rat model of folate receptor autoantibodies; E.V. Quadros. (New-York, United States)
“…Testing for FR autoantibodies and folinic acic supplementation could have a major impact in preventing and treating autism”.
2.   Understanding the role of vitamin B12 deficiency in de novo thymidylate biosynthesis.
A.M. Palmer. (New York, United States):
“These studies will enable us to establish the role of B12 deficiency in nucleotide biosynthesis and genome stability”.
3. Metabolomics reveals new pathways and candidate biomarkers of vitamin B12 status, effects of B12 on myelinated peripheral nerve conduction and interaction with folate status.
A. Brito (California, United States)
“Metabolomics reveals new pathways and candidate biomarkers of B12 status and effects of B12 on myelinated peripheral nerve conduction.  The interaction with folate status is under assessment.  The combined indicator of B12 status had the highest capacity to identify associations with metabolomics as compared with any single biomarker”.

 

4. Impact of elevated levels of plasma homocysteine and impaired DNA repair in a mouse model of vascular cognitive impairment
N.M. Jadavji, (Berlin, Germany)
“The results suggest that a combination of hyperhomocysteinia, chronic hypoperfusion or impaired DNA synthesis is required for memory impairments, whereas MTHFR deficiency alone has no effect on learning.  Additionally, cortical choline metabolism is disrupted in MTHFR deficient mice with chronic hypoperfusion”.
5. Methyl donor deficiency impairs differentiation of pre-osteoblasts through disruption of functional interaction between peroxisome proliferator-activated receptor-gamma coactivator-1 alpha and vitamin D receptor
E. Feigerlova (Nancy, France):
“The data presented here provide new mechanistic insights into regulation of human osteoblast differentiation demonstrating for the first time crucial role of PGC-1α-VDR functional interaction, dramatic effect of MDD on the nuclear action of 1,25(OH)2D3 through hypomethylation of PGC-1α and sequestration of VDR in a form of the HSP90-VDR complex. This prevents the hormone binding to PGC-1α and leads to impaired expression of target genes ultimately directing cell differentiation toward a more adipogenic phenotype.”

Session 3: Metabolic, Cellular and Tissular Compartments of the One Carbon Metabolism

Patrick J Stover (Ithaca, New York)

“The results from these studies suggest a convergence of the NTD-associated risk factors to a single pathway responsible for folic-acid responsive NTDs.”

  1. MPV17 Mitochondrial Inner Membrane Protein Loss-of-Function Causes MDS and Altered One-Carbon Metabolism

J Alonzo (New York, USA)

“Mutations in the human MPV17 gene are known to cause Mitochondrial DNA depletion syndrome (MDS). Our results suggest that MPV17 may play an important role in mitochondrial one-carbon metabolism and maintaining mtDA integrity. Understanding the mechanism by which MPV17 affects mtDNA and causes changes in one-carbon metabolism may provide insight into better medical treatment and prognosis for MDS patients.”

 2. Methyl deficient diet promotes colitis and SIRT1-mediated endoplasmic reticulum stress

H Melham (Nancy, France)

“Adding either vitamin B12, S-adenosylmethionine, or a SIRT1 activator (SRT1720) reduced the unfolded protein response (UPR) in vitro. In rats, SIRT1 activation by SRT1720 prevented colitis by reducing acetylation of HSF1 and increasing the expression of BIP, HSP27 and HSP90. Immunohistochemistry showed impairment of SIRT1 in the colonic epithelium of IBD patients. SIRT1 is a master regulator of ER stress and severity of experimental colitis in cases of methyl donor deficiency (MDD). It could deserve further interest as a therapeutic target of inflammatory bowel disease.”

 

3. S-Adenosylhomocysteine promotes endothelial activation through NF-KB activation

M Barroso (Lisbon, Portugal. Boston, USA)

“Our results show that S-Adenosylhomocysteine (SAH) accumulation leads to the activation of NF-KB canonical and ono-canonical pathways. NF-KB activation induced the expression of adhesion molecules and cytokines that promote pro-inflammatory activation of endothelial cells and leukocyte recruitment, important steps in atherogenesis. Here we demonstrate a new association between SAH and NF-KB that may promote cardiovascular diseases.”

4. Interplay between folate, S-adenosylhomocysteine and protein methylation in human endothelial cells: the importance of methionine availability

R Castro (Lisbon, Portugal)

“In endothelial cells, methionine excess constrains the ability of folate to restore the intracellular methylation potential. Interestingly, our findings may explain why in randomised trials folic acid lessened plasma tHcy, but failed to reduce cardiovascular risk, suggesting that folate interventions will be vascular-protective only within a context of low methionine availability.”

SESSION 4: ENZYMES OF THE ONE CARBON METABOLISM: LESSONS FROM GENETIC DISEASES AND GENETIC MODELS

1. Strategies to correct homocystinuria in mouse models of CBS deficiency

 WD Kruger (Philadelphia, USA)

 “Our findings indicate that while betaine supplementation does have some beneficial effects, it is not as effective and methionine restriction for reversing the phenotypes associated with severe CBS deficiency in the Tg-I278T Cbs-/- mouse model of CBS deficiency.”

2. Correction of cognitive impairment in a model of hyperhomocysteinemia due to cystathionine beta synthase

 Nathalie Janel (Paris, France)

 “We conclude that specific hepatic Dyrk1A gene transfer restores the molecular mechanisms altered by Dyrk1A overexpression in brain of CBS deficient mice.”

3. Does hyperhomocysteinemia affect collagen and elastin cross-links in a mouse model of cystathionine ?-synthase deficiency?

 J Perla-Kaján (Poznan, Poland)

 “Although susceptible to N-homocysteinylation in vivo, elastin and collagen do not show significantly affected cross-linking in Cbs-deficient mice.”

 4. Body composition, lipid metabolism and SCD-1 activity in patients with classical homocystinuria

S Poloni (Porto Alegre, Brazil)

 “This study suggests that, in classical homocystinuria, altered SAA metabolism suppresses SCD-1 activity also in humans. The reduction of leptin, a major regulator of SCD-1 expression, is in agreement with the findings in animal models of hyperhomocysteinemia.”

5. Methylation imbalance in a mouse model of CBS deficiency induces liver phospholipids remodelage

 A Imbard (Paris, France; Chatenay-Malabry, France)

 “Accumulation of satured PC and unsaturated PE and decrease in unsaturated PC suggest an inhibition of the PEMT pathway which uses preferentially unsaturated PE for PC synthesis1. Moreover the increased CHPT1 expression and increased saturated PC might suggest an induction of the Kennedy pathway to maintain the PC synthesis.”

Session 5: Absorption, Blood and Cellular Transport of B Vitamins

1. Absorption and blood/cellular transport of B vitamins involved in one-carbon metabolism

David H Alpers(St Louis)

 “the intestinal transporters for folate and cobalamin differ greatly in their structure. The compartmentalization of folate and cobalamin within the body is determined in part by these specific features, and can be understood in terms of classical pharmacokinetics. Because of these complexities it is not surprising that the bioavailability of folate and cobalamin can be variable in health and disease.”

2. Lysosomal transport of cobalamin: What we know and what we don’t know?

Frank Rutsch (Munster, Germany)

“Preliminary experiments so far have failed to prove transmembrane transport of cobalamin by either one or both of the identified proteins. While most recent data suggest an interaction of LMBD1 with ABCD4 and with the cytosolic protein MMACHC, the exact mechanism of lysosomal cobalamin export is still mysterious.”

3. Transcytosis in the vascular endothelium recycles uncommitted vitamin B12
L Hannibal (Ohio, United States; Erlangen, Germany)
“Our results suggest a mechanism whereby the vascular endothelium recycles uncommitted intracellular cobalamin for downstream usage.”

4. Proteomics and Genomics approach to understand mechanism of Cysteine induced toxicity in yeast
Ajay Bhat (New Delhi, India)
“Leucine plays an important role in survival during cysteine induced stress. By overlapping the proteomics and genomics data we found that cysteine affects the expression of ribosomal proteins and protein degradation pathways and expression of amino acid metabolism serve as a response for survival during high cysteine levels.”

5. Stable isotope dilution assays for clinical analyses of folates and other one-carbon metabolites
M. Kopp (Freising, Germany)
“The miniaturized methods using sample volumes as low as 50 µL and weighed portions of 5-20 mg will allow to assess the status of folates and further biomarkers of an impaired one-carbon metabolism.”

SESSION 6: INHERITED DISORDERS OF ONE-CARBON METABOLISM AT THE AGE OF NGS

1. Intracellular cobalamin partitioning, advances and unanswered questions
B. Fowler (Zürich, Switzerland)
“Current knowledge points to a role of MMADHC in at the branch point of Cbl delivery to the mitochondrial and cytoplasmic target enzymes. Emerging studies have shown that MMADHC does not bind Cbl itself but can interact with MMACHC. In spite of these advances much regarding the exact molecular function and interactions of these intriguing proteins remains to be explained and key to this will be knowledge of the 3-D structure of the MMADHC protein.”

2. Search for the molecular basis of two complementationconfirmed atypical mut patients
Jordan Chu (Quebec, Canada)
“It is unexpected that two mutations in MUT were not found in these two patients, considering the high reliability of complementation analysis in diagnosing inborn errors of cobalamin metabolism. Regulatory or deep intronic mutations not assessed by the gene panel may be causative of the mut phenotypes. Alternatively, the patient with heterozygous mutations in MUT and MCEE could be an instance of synergistic heterozygosity. For the patient with no currently identified mutations, there may be mutations in unexpected genes controlling the expression of MUT, as has recently been shown for HCFC1 and MMACHC.”

3. Investigating a novel inborn error of cobalamin metabolism
Mihaela Pupavac (Quebec, Canada)
“These data suggest that the cellular defect in that patient’s fibroblasts affects internalization of the TC-Cbl complex after binding to its cell surface receptor, but before degradation in the lysosome.”

4. New generation sequencing (NGS) identifies digenism in two families, with MTHFR/POLG and MTHFD/GIF mutations, respectively
Guéant JL (Nancy, France)
“NGS found digenism, with POLG mutation in adult twins with MTHFR inherited deficiency and unusual clinical presentation of spastic paraparesis. NGS led us also to find a MTHFD compound mutation in two siblings with GIF mutation and severe immunodeficiency.”

5. Loss of LMBD1 protein results in gastrulation defects during mouse embryogenesis
I Buers (Muenster, Germany)
“Crossbreeding of the Lmbrd1flox3/neo-mice with Credeleter mice resulted in the deletion of the third exon of the Lmbrd1 gene and the loss of the LMBD1 protein. Our results show that loss of function of Lmbrd1 leads to early embryonic lethality in mice due to gastrulation defects. We conclude functional LMBD1 plays an essential role in early developmental processes in mice.”

6. Excessive Folic Acid (FA) Intake and Relation to Adverse Effects
Jacob Selhub (Boston, USA)
“We have shown that the for unilateral retinoblastoma in offspring is higher in mothers who were homozygotes for the 19bp deletion in the DHFR gene and took FA supplement. Elderly with this polymorphism had lower memory and executive scores, both being significantly worse in those with high plasma folate.”

SESSION 7: ONE CARBON METABOLISM, EPIGENOMICS AND EPIGENETICS

1. Epigenomic Dysregulations in Vitamin B12 and Folate Deficiencies
Jean-Louis Guéan (Nancy, France)
“In conclusion, the deficiency in folate and vitamin B12 influences cell proliferation, differentiation, reticulum stress and energy metabolism through epigenomic mechanisms related to imbalanced acetylation/methylation. Some but not all of these effects reflect their key role in SAM synthesis.”

2. Maternal vitamin B12 deficiency leads to altered DNA methylation in genes involved in fatty acid metabolism as revealed by whole genome methylation analysis using MeDIP-Seq
Shantanu Sengupta (New Delhi, India)
“Maternal Vitamin B12 deficiency leads to altered methylation in the offsprings, which leads to conditions like dyslipidemia in adult pups. This alteration can be partially reversed by supplementation of the vitamin B12 either at conception or parturition.”

3. Effect of MTHFR 677C>T on genome-wide DNA methylation: A meta-analysis
Pooja R Mandaviya (Rotterdam, Netherlands)
“Genome-wide meta-analysis of homocysteineassociated SNPs showed significant meQTLs. In the coming months, the results from this discovery analysis will be replicated in additional studies and presented at the meeting.”

4. B12 Intervention Influences Methylation of Genes Associated with Type 2 Diabetes and Its Intermediate Traits
DK Yadav (Hyderabad, India)
“We demonstrate that B12 supplementation alters the methylation of genes influencing intermediate traits of T2D like obesity (FTO), insulin resistance and secretion (TCF7L2). Our study provides a novel ‘epigenetic’ explanation for the association between one-carbon metabolism and risk of adiposity, insulin resistance and diabetes.”

5. Global and MTHFR gene specific methylation and its role in Preeclampsia
MP Sachdeva (Delhi, India)
“The study highlights the importance of global methylation in the causation of PE i.e. hypermethylation at global levels among PE cases. The study also suggests that MTHFR C677T polymorphism in heterozygous condition along with hyper global methylation is posing a risk for pre-eclampsia.”

SESSION 8: CARBON METABOLISM IN DEVELOPMENT AND BIRTH DEFECTS: LESSONS FROM EXPERIMENTAL MODELS, GENETICS AND POPULATION STUDIES
1. Folate one-carbon metabolism and development: a requirement for the glycine cleavage system in neural tube closure and brain development
NDE Greene (London, UK)
“Gldc-deficiency in mice causes two distinct phenotypes, affecting neural tube closure and later brain development. These findings support the hypothesis that GCS genes may represent susceptibility genes for NTDs in humans, in addition to their known causative role in NKH. Prevention of NTDs by formate suggests that GCS defects cause NTDs through limiting supply of one-carbon units from mitochondrial FOCM. These NTDs may be preventable but require additional/alternative approaches to folic acid.”

2. Mouse ontogenesis of enzymes involved in 1-C metabolism
A Imbard (Paris, France; Chatenay-Malabry, France)
“The gene expression of enzymes involved in homocysteine and related metabolisms show dramatic changes during development and are tissue specific.”

3. Preventable neural tube defects in Germany
Rima Obeid (Denmark)
“Germany shows a two-fold epidemic of NTDs compared to other countries that implement FA fortification. We demonstrate the potential of live and cost saving by implementing FA fortification as a population-based public health strategy. Primary prevention of NTDs by FA is expected to reduce child mortality and morbidity and reduce costs for health care.”

4. L-5-Methyltetrahydrofolate supplementation increases blood folate concentrations to a greater extent than folic acid supplementation in Malaysian women
RE Aleliunas (Vancouver, Canada)
“These findings suggest differential effects of L-5MTHF supplementation compared to FA supplementation on blood folate concentrations in Malaysian women with no FA fortification.”

5. Gestational methyl donor deficiency affects embryonic development through altered microRNA pathways: benefit of a late folate supplementation
A Geoffroy (Vandœuvre-lès-Nancy, France)
“Our data outline the potential role of let-7 and miR-34 and their related signaling pathways in the developmental abnormalities consecutive to gestational methyl donor deficiency, and support the likely usefulness of late folate supplementation to prevent birth defects.”

SESSION 9: ONE CARBON METABOLISM, PREGNANCY AND FOETAL PROGRAMMING.

1. 1-C metabolism and risk of diabetes and cardiovascular disease in Indians
CS Yajnik (Pune, India)
“We have described a role for deranged maternal 1-C metabolism in fetal programming of cardiometabolic risk in the offspring. A vit B12 and multimicronutrient intervention trial has been started in adolescents to reduce the risk of diabetes and CVD in the offspring. Isotopic investigations during methionine load test will help investigate contribution of transmethylation and transsulfuration pathways to the derangement in Indians.”
2. Early pregnancy B vitamin status, one carbon metabolism and pregnancy outcome
MM Murphy (Instituto Carlos III)
“Cessation of folic acid supplement use after the first trimester is associated with a sharp drop in plasma folate status and enhanced conversion of betaine to dimethylglycine. Dimethylglycine production is also higher in mothers with low folate status than in those with normal-high folate status. Early pregnancy homocysteine is a strong and significant predictor of intrauterine growth retardation. The presence of the MTHFR 677C>T polymorphism in either mothers or fathers is a risk factor for pathological maternal uterine artery waveforms and elevated resistance to blood flow by Doppler analysis. The effects of high doses of folic acid on one carbon metabolism in mothers with low early pregnancy cobalamin status and on foetal growth from the Reus- Tarragona Birth Cohort will also be presented.”

3. Seminal Quality And Pesticide Exposure – Interrelationship With Homocysteine, Folate And Vitamin B12
R Delport (Pretoria, South Africa)
“Low plasma tHcy concentrations as well as low vitamin B12 and folate status appear to be implicated in impaired male fertility, both in the presence or absence of DDTuptake due to differing pathophysiological mechanisms. The findings in relation to plasma tHcy and spermatogenesis are unexpected.”

4. Father’s In Utero and Postweaning Dietary Folic Acid Intake Affects the Health of his Offspring
AJ MacFarlane (Ottawa, ON, Canada)
“The data indicate that FA deficiency in fathers’ may cause congenital anomalies and SGA in their offspring, and influences heritable metabolic programming of one carbon metabolism in their unexposed descendants. Ongoing analyses will examine the effect of paternal FA intake on the sperm methylome.”

5. Methyl donor deficiency during gestation and lactation produces hepatosteatosis in rat offspring fed a high-fat diet in adult life
A Bison (Vandœuvrelès-Nancy, France)
“These results suggest investigating whether MDD during gestation and lactation is a risk factor of steato-hepatitis in subjects who are subsequently exposed to high fat diet.”

6. Elevated levels of S-adenosylhomocysteine, DNA hypomethylation of placental growth factor and global DNA hypomethylation in placentas of preeclamptic pregnancies
SG Heil (Rotterdam, The Netherlands)
“This study shows elevated levels of SAH and hypomethylation of LINE-1 and PGF genes in placental tissue of PE patients, which suggests that DNA methylation might be an important mechanism that needs to be further addressed in preeclampsia.”

SESSION 10: CHOLINE AND BETAINE IN EARLY AND LATER LIFE

1. Structural and catalytic features of betaine-homocysteine Smethyltransferase enzymes: metabolic implications for sulfur amino acid homeostasis.
TA Garrow (Urbana-Champaign, USA)
“BHMT and BHMT-2 are zinc- and potassiumdependent methyltransferases, and at least BHMT is required for normal homocysteine metabolism.”

2. Effects of the BHMT c.716G>A polymorphism on the betaine dimethylglycine pathway during pregnancy
JM Colomina (Instituto Carlos III, Spain)
“From mid-pregnancy, in women with high folate status, plasma DMG and DMG/BET, that depend on BHMT function, were lower for the BHMT c.716AA compared to GG genotype.”

3. Elevated plasma dimethylglycine predicts cardiovascular risk only when plasma methylmalonic acid is also high
V Lysne (Bergen, Norway)
“In this prospective cohort study elevated plasma DMG was associated with increased risk of AMI and cardiovascular and total mortality only among those who also had high plasma MMA. Elevated plasma MMA was associated with increased total mortality also when plasma DMG was low. This suggests that risk previously demonstrated with plasma DMG among cardiovascular patients is modified,and perhaps better explained by plasma MMA

4. From liver to brain dysfunction – a pilot study in methionine and choline deficient rats
Nur Abu Ahmad (University of Jerusalem, Israel)
“In a rat model of MCD-induced NAFLD, betaine administration exerts hepatoprotective and possibly neuroprotective effects. Because the brain lacks BHMT, the improvement in brain function with betaine administration is likely due to partial restoration of the export of methionine, choline and phospholipids from liver to brain. Ongoing work in this model will provide insight into liver-brain cross-talk in the context of one-carbon metabolism.”

5. The effect of orally administered alpha glycerophosphocholine in senescence-accelerated mouse P/8 line
Sachi Shibata (Hiroshima, JAPAN)
“In the novel object recognition test, the scores of GPC group were significantly better (P < 0.05) than control group. Immunohistochemical analysis for immunoglobulin extravasation in brain revealed that -GPC did not protect bloodbrain barrier. In the blood analysis, -GPC group showed significantly lower values in total cholesterol and free fatty acids. Although steatosis and other lesions were observed in hematoxylin and eosin-stained livers in control group, the livers of -GPC group showed less pathological lesions. From the above results, the oral intake of -GPC is likely to decrease the risk of diseases associated with aging.”

SESSION 11: GENETIC DETERMINANTS OF THE ONE CARBON METABOLISM IN POPULATIONS
1. Dissecting the contribution of genetic variation on one carbon metabolites
LC Brody (Bethesda, Maryland)
“Our GWAS results have identified genetic variants that contribute to inter-individual differences in the function of the folate/vitamin B12 metabolic pathways. These data will allow us to focus on small number genes when asking questions about the role of these pathways in numerous disease states.”

2. The dihydrofolatereductase (DHFR) 19 base-pair deletion polymorphism modifies the association of folate status with memory
AM Troen (Boston, MA, USA; Jerusalem, Israel)
“This study identifies a putative gene-nutrient interaction that, if confirmed, would predict that a sizable minority carrying the del/del genotype might not benefit from high-folate status and could see a worsening of memory. Understanding how genetic variation affects responses to highfolate exposure will help weigh the risks and benefits of folate supplementation for individuals and public health.”

3. Genetic determinants of vitamin B12 levels in Indians
SS Nongmaithem (Hyderabad, India)
“We provide evidence that although there are common genetic determinants of vitamin B12 levels, significant heterogeneity at genetic variant level remains. Tracking of vitamin B12 concentrations with genotypes suggests a causal association between the top 10 hits and plasma vitamin B12 levels in Indians.”

4. Genetic modifiers of folate, vitamin B12 and homocysteine status in a nationally representative sample of the Canadian population
AJ MacFarlane (Ottawa, ON, Canada)
“We identified novel associations between SNPs in CD320 and DNMT2, which had been previously associated with neural tube defects, and vitamin B12 status, and between SNPs in SHMT1, which had been previously associated with colorectal cancer and cardiovascular disease risk, and RBC folate status. These novel associations provide a plausible metabolic rationale for the association of these SNPs with B-vitamin related diseases. We also observed a novel association between a SNP in CUBN with RBC folate and confirmed the association of a number of SNPs with B-vitamin status in this large crosssectional study. Additional studies will examine the impact of dietary and supplemental folic acid intake on the associations between these SNPs and RBC folate, serum vitamin B12 and plasma Hcy.”

5. A 10 year follow-up study to investigate blood pressure in healthy male adults screened for the C677T polymorphism in MTHFR
E Hughes (Coleraine, Northern Ireland)
“Within this sample of generally healthy males the MTHFR 677TT genotype appears to be a significant factor in the development of hypertension in middle age however this requires further investigation.”

6. Associations between homocysteine, the MTHFR 677C>T polymorphism and hypertension in adults
G Ornosa1 (Instituto Carlos III, Spain)
“High tHcy or the mutant allele of the MTHFR 677C>T polymorphism were risk factors for hypertension in the population studied. The effect of the MTHFR 677C>T polymorphism on hypertension in the population appears to be driven by its effect in men.”

SESSION 12: BIOMARKERS OF THE ONE CARBON METABOLISM AND B VITAMINS IN MEDICAL PRACTICE AND POPULATION STUDIES
1. Vitamin B12 biomarkers: Diagnostic tool or diagnostic truth
E Nexo (Aarhus, Denmark)
“The discussion about the optimal use of biomarkers for diagnosing B12 deficiency will stop only when we reach consensus about the condition we want to identify. Once deficiency is diagnosed, its cause should be revealed prior to treatment.”

2. Circulating Levels of Trimethyllysine Predicts Incident Myocardial Infarction in Patients With Stable Angina Pectoris depending on Vitamin B2 status
Løland KH (Bergen, Norway)
“Among patients with SAP, serum TML predicted time to MI in both univariate and multivariate statistical models adjusted for traditional risk factors. The effect was more pronounced in patients with elevated levels of B2. 1Løland KH, Bleie O, Borgeraas H, Strand E, Ueland PM, Svardal A, Nordrehaug JE, Nygård O. The association between progression of atherosclerosis and the methylated amino acids asymmetric dimethylarginine and trimethyllysine.”

3. Lower CSF 3-Orthomethyldopa Levels Related with One Carbon Metabolism in First Episode Psychosis
Baris Bahar (Istanbul, TURKEY)
“In psychosis, there might be a defect in the synthesis of dopa and inactivation or removal by methylation as form of 3-OMD in the central nervous system. Higher serum methionine levels as assessed together with low RBC folate indicates important evidence for diminished synthesis and demand of SAM as active single carbon carrier.”

4. Lipid and Homocysteine metabolism in a Mendelian population: A study from rural and urban North India.
K N Saraswathy (Delhi, New Delhi)
“It can be concluded that lipid and homocysteine pathways and their interaction are different in rural/urban settings. Moreover, the influence of nutritional deficiencies on homocysteine levels is not so effective in urban areas. Hence, because of high levels of lipid indices in urban areas, the interaction between lipid and homocysteine might be more pronounced in near future in this selected Mendelian population. Thus the study emphasizes on the critical role of geneenvironment interaction and put forth the concept of geography, community specificity in understanding complex diseases.”

5. The one-carbon metabolism in a cohort of 323 healthy children and adolescents
H Caldeira Araújo (Funchal, Portugal)
“Our pediatric population showed a significant decline with age of folates, total Cbl, holo-TC and MMA plasma concentrations, and a considerable increase in tHcy levels similarly to other populations. However, Portuguese adolescents showed lower levels of folates, Cbl and holo-TC than other European populations of the same age, possibly reflecting differences in diet or food fortification. Moreover, an inverse correlation was observed between plasma folates and tHcy in both age groups and between MMA and holo-TC in the older group showing the potential importance of folates in reduction of Hcy and of MMA as an early indicator of active vitamin B12 deficiency.”

6. Methylmalonic acid concentration quantified in newborn screening cards for vitamin B12 status assessment at birth
TH Schroder (Vancouver BC, Canada)
“This is, to our knowledge, the first study to reliably quantify MMA in newborn screening cards and to derive a reference interval for MMA in healthy term newborns. Our future directions are to determine the rate of B12 inadequacy in South-Asian newborns by quantifying MMA in routinely collected newborn blood spots.”

7. Identification of a coding SNP in transcobalamin II affecting the analysis of holotranscobalamin using the monoclonal antibody
A Sobczy ska-Malefora (London, UK)
“The minor allele of TCN2 rs35838082 appears to interfere with detection of holoTC in the Active B12 test. This missense change may alter the epitope recognized by the detection antibody. Laboratories using the holoTC assay should be aware of this genetic variant and use confirmatory tests in cases with extremely low holoTC. The biological significance of this variant is currently unknown.”

8. The homocysteine theory: Dead or alive?
H Refsum (University of Oslo, Norway)
“I will conclude that the theory is still valid, but in a different way than we first anticipated, namely that the beneficial effect is confined to subgroups where B vitamin status is suboptimal and other treatments are missing. Thus, the theory is fully alive and there are still major public health implications of the homocysteine theory.”

SESSION 13: ONE CARBON METABOLISM AND DISEASED AGEING: LESSONS FROM EXPERIMENTAL MODELS AND POPULATION STUDIES
1. One carbon metabolism and diseased ageing: Decoding folate and vitamin B12 biomarker patterns in older adults
Molloy A.M (Trinity College, Dublin)
Few data exist on how folate and B12 biomarkers respond to these phenomena, although current research suggests that circumstances leading to a substantial imbalance between the status of each vitamin may exacerbate the manifestations of disease. In this presentation, the patterns of folate and vitamin B12 status biomarkers in a large cohort of 5186 older persons with early signs of cognitive dysfunction, bone disease or metabolic disease will be described.

2. Persistence of N-homocysteinylation of structural proteins and gastric mucosa inflammation in adult and aged rats after fetal and early postnatal exposure to methyl donor deficiency
C Bossenmeyer-Pourié (Vandœuvre-lès-Nancy, France)
“The deleterious gastric effects of MDD during gestation and lactation were only partly reversed by the ingestion of a normal diet after weaning. Some imprinting effects of early MDD on gastric wall structure (inflammation, apoptosis, oxidative stress, and ulcerative states) are, however, rather definitive. This suggests the in utero development period is of critical importance in terms of availability of B vitamins and other methyl donors for maintaining the cellular integrity of gastric mucosa.”

3. Vitamin B6 catabolism and long-term mortality risk
A Ulvik1 (Bergen, Norway)
“The study confirmed that inflammation confounds the association between plasma PLP and mortality. The PArindex was a strong risk-predictor across cohorts, particularly in patient-groups at perceived low risk. The present findings link cellular immunity and aldehyde stress to long-term mortality.”

4. Prospective study of telomere length and LINE-1 methylation in peripheral blood cells: the role of B and/or D vitamins supplementation
Irene Pusceddu (Homburg/Saar, Germany)
“The results suggest a possible effect of Bvitamins for telomere biology in blood cells. Sub-optimal Bvitamins status and hyperhomocysteinemia are associated with altered DNA methylation and telomere length.”

5. Elevated plasma vitamin B12 and risk of venous thromboembolism in cancer patients
JFB Arendt (Aarhus N, Denmark)
“High vitamin B12 levels among cancer patients were associated with an increased VTE risk within 30 days after cancer diagnosis. However, this finding should be interpreted cautiously due to the small number of VTE events.”

SESSION 14: HEALTH AND NUTRITION EXAMINATION SURVEY IN B VITAMINS AND CHOLINE, WORLDWIDE
1. Population-based assessment of vitamin B12 status in the era of folic acid fortification
JW Miller (NJ, USA)
“Based solely on tB12 <148 pmol/L, overall prevalence of low B12 status in the United States has been estimated to be ~2%, with the highest prevalence observed in older adults (~3-6%). Using the same cutoff value for low tB12, dramatically higher prevalence rates (>20%) have been observed in both children and young adults in diverse locations, such as Guatemala, Mexico, India, Kenya, and Israel. Higher cutoff values for low tB12 have been proposed (e.g. 221 or 258 pmol/L), which predictably provide higher, but perhaps overestimated prevalence rates. Better accuracy in estimating prevalence is likely acquired by combining B12 biomarkers, such as tB12 or holoTC with MMA or Hcy. Such strategies typically estimate lower prevalence rates of B12 insufficiency than using any biomarker alone, but are highly influenced by what cutoff values are chosen. Recently, a strategy of using all four B12 biomarkers in one formula (combined B12 or cB12) has been proposed1 that may provide increased accuracy for determining the prevalence of low B12 status.”

2. Folate status and concentrations of serum folate forms in the US population: National Health and Nutrition Examination Survey 2011–2012
CM Pfeiffer (Atlanta, GA, USA)
“These first-time population data for serum folate forms generally show similar associations with demographic, physiologic, and lifestyle variables as serum total folate. Patterns observed for MeFox may suggest altered folate metabolism dependent on biological characteristics.”

3. Obesity and osmolality are associated with decreased concentrations of serum folate
E Laird (Dublin, Ireland)
“Hydration status is an important factor to consider in evaluating the effect of BMI on blood folate concentrations.”

4. Unmetabolized folic acid in serum after single folic acid or B-complex supplementation
Rima Obeid (Homburg/Saar, Germany)
“Compared to FA, B12 and B6, FA supplements caused higher prevalence of UMFA in serum of elderly people. Higher FA conversion into 5-MethylTHF and less occurrence of UMFA post-intervention were probably related to improving vitamin B6 status. Population data on serum folate forms should be interpreted in relation to intake and status of other vitamins included in multivitamin supplements, in particular those involved in folate metabolism.”

5. Poor biochemical riboflavin status common among nonsupplemented older adults in Northern Ireland and the Lower Mainland, British Columbia, Canada
KC Whitfield (Vancouver, Canada)
“Low riboflavin status may be a generalized problem in older adults. Typical dietary intakes from food alone, even with fortification, may be inadequate to sustain normal biomarker status. Acknowledgements: UBC Vitamin Research Fund and United Kingdom Food Standards Agency.”

SESSION 15: B VITAMINS AND HOMOCYSTEINE IN NEUROLOGICAL AND BEHAVIOUR DISORDERS
1. A good omega-3 fatty acid status is required for B vitamins to protect the brain: a retrospective look at VITACOG
“The beneficial effects of B vitamin treatment on brain atrophy and cognition were found only in subjects with high plasma omega-3 FA. Likewise, the beneficial effect of omega 3 FA on brain atrophy is confined to subjects with good B vitamin status. The results highlight the importance of identifying subgroups likely to benefit in clinical trials. The findings provide the basis for a component of a risk-reduction programme for Alzheimer’s disease in those with Mild Cognitive Impairment. Further clinical trials are needed.”

2. Mutations in human Capicua gene underlies folate transport defects in children with the Cerebral Folate Deficiency syndrome
RH Finnell (Austin, TX, USA)
“The CIC protein is a HMG-box transcriptional repressor, with the DNA binding domain recognizing an octomer sequence T(G/C)AATG(A/G)A. The de novo mutation p. R353X is predicted to yield a truncated protein containing the HMG box; therefore, it can bind to its targets in the promoter regions of folate genes FOLR1, MTHFR, DHFR and MTHFD1, and in the 3’ un-translated region (3’UTR) of SLC19A1. Clearly CIC mutations may be involved in the development of CFD symptoms by suppressing folate metabolism and transporter genes. Results from functional studies will be presented.”

3. Folate receptor antibodies are associated with infantile autism and juvenile schizophrenia
V T Ramaekers (CHU Liège, Belgium)
“Our findings suggest that FR autoimmunity is the most important marker for autism identified among 89% of affected children. FR antibodies in either one or both parents, represents another mechanism for autism in the child. The development of FR antibodies during adolescence also predisposes to intractable schizophrenia. These findings underline the importance for early screening of FR autoantibodies in autism and schizophrenia because treatment with folinic acid leads to considerable improvement in core symptoms”

4. Vitamin B12, folate, and sulfur amino-acids in relation to the rate of brain atrophy in subjects at risk of dementia: a longitudinal population based study
Babak Hooshmand (Stockholm, Sweden)
“Higher concentrations of vitamin B12 and lower levels of homocysteine are associated with decreased rate of brain volume loss in older adults, even in non-demented elderly.”

5. Impact of vitamin B12 deficiency on the brain of the mouse model invalidated for the CD320 gene
N. Dreumont (Vandoeuvre-lès-Nancy, France)
“The CD320 mouse model has a unique phenotype of vitamin B12 deficiency that specifically affects the brain. We are using it to define the neuropathological manifestations of vitamin B12 deficiency and to identify the genes and pathways involved in the dysregulation of myelination in the central and peripheral nervous system.”

6. A rat model for folate receptor antibody-mediated behavioral deficits
JM Sequeira (Brooklyn, NY, USA)
“Exposure to FR antibodies during gestation produces severe learning deficits in the offspring. Folinic acid and dexamethasone appear to prevent the functional deficits induced by the antibody. These results may have a major impact in preventing and treating autism.”

SESSION 16: VITAMIN B2, VITAMIN B6, KYNURENINE AND TRYPTOPHAN
1. Direct and Functional Biomarkers of Vitamin B6 Status
PM Ueland (Bergen, Norway)
“This review will summarize and compare different biomarkers of vitamin B6 status, with emphasis on the novel biomarkers based on metabolite ratios.”

2. Influence of Vitamin B6 Status on the Function of the Transsulfuration Pathway
Jesse F. Gregory (Gainesville, USA)
“Wide individual variation in responses of the H2S biomarkers to such perturbations of human vitamin B6 status suggests that that the resulting modulation of H2S production may have physiological consequences in a subset of people.”

3. Plasma pyridoxal 5’-phosphate concentration decreases while cystathionine concentration increases during pregnancy: results of a prospective cohort study.
MF Mujica-Coopman (Vancouver BC, Canada)
“Plasma PLP during pregnancy was positively correlated with cysteine, methionine and glutathione and negatively with cystathionine. The increase in plasma cystathionine concentration throughout pregnancy (despite expected pregnancy-related hemodilution) might indicate functional consequences of the decreasing plasma PLP concentration and reflect maternal intracellular B6 deficiency.”

4. An observational investigation of roles of vitamin B6, riboflavin and their interaction, and with MTHFR genotype, as determinants of cognitive performance in ageing: Results from the TUDA Ageing Cohort Study
CF Hughes (Coleraine, Northern Ireland)
“Low vitamin B6 and riboflavin, although often overlooked, may play important roles in maintaining cognitive health in ageing. Furthermore homozygosity for the MTHFR C677T polymorphism in combination with low riboflavin status may significantly increase the risk of cognitive dysfunction. Further research is required, ideally in the form of randomised controlled trials in order to determine whether a causative relationship exists.”

SESSION 17: HOMOCYSTEINE, VITAMINS B AND CHOLINE IN CARDIOVASCULAR DISEASES, COMPONENTS OF METABOLIC SYNDROME AND BONE DISEASES

1. Homocysteine and kidney failure: do tangled clues start getting unraveled?
Diego Ingrosso (Naples, Italy)
“Derangements of sulfur amino acid metabolism offers new highlights in cardiovascular medicine for their potential involvement in the genesis of vascular damage by triggering inflammatory response. Several differences in the metabolism of sulfur amino acids and their derivatives in kidney failure and normal individuals can be underlined.”

2. Plasma trimethylamine N-oxide is related to glucose, cholesterol and methyl group metabolism
Rima Obeid (Homburg/Saar, Germany; Aarhus C, Denmark)
“TMAO is increased in diabetics and end stage renal disease and is predicted by plasma glucose and cholesterol homeostasis makers, methylation markers, methylmalonic acid, and plasma electrolytes. The role of TMAO as a marker for cholesterol transport may be regulated by methylation.”

3. Hyperhomocysteinaemia and B vitamin intakes in patients with a history of cardiovascular disease
A Sobczyska-Malefora (London, UK)
“The intake of B vitamins was insufficient in most patients. This was reflected in a high prevalence of hyperhomocysteinaemia for both patients, with pre-existing thromboembolic disease as well as those patients, mainly with atrial fibrillation, who were taking warfarin as a prophylactic therapy.”

4. Homocysteine-thiolactone and cardiovascular disease in B-vitamin trials
Hieronim Jakubowski (Poznan, Poland)
“Associations of Hcy-thiolactone with CVD history, gender, smoking, hypertension, diabetes, microalbuminuria, MTHFR 677C->T polymorphism, plasma B-vitamins, betaine, tHcy, glomerular filtration rate (GFR), and circulating inflammation markers (CRP, neopterin, KTR-kynurenine/tryptophan ratio) are also described.”

5. Interleukin-6, choline and type 2 diabetes associated or not with essential hypertension
L. L. Hurjui (Iasi, Romania)
“The present work brings evidence that patients with established T2DM have a different cytokine profile compared to healthy controls and this could indicate changes in the immune function in T2DM patients. Endothelial dysfunction comprises a number of functional alterations in the vascular endothelium that are associated with DM, including changes in vasoregulation, enhanced generation of reactive oxygen intermediates, inflammatory activation, and altered barrier function. Improvement of choline deficiency is important for preventing from life-style related disease associated with aging and oxidative stress.”

6. Association of dietary choline with incident diabetes mellitus in patients with stable angina pectoris
T Karlsson (Bergen, Norway)
“Higher dietary intake of choline from phosphatidylcholine was associated with increased risk of type 2 diabetes only in patients not treated with vitamin B6.”

7. Targeted metabolomics of the methylation cycle in chronic kidney disease and the effect of oral SAMe.
T Bottiglieri (Dallas, TX)
“Oral SAMe for 6 weeks did not adversely affect metabolites of the methylation c cycle in patients with ESRD, but did improve the plasma SAM/SAH ratio promoting methylation. SAMe was well tolerated with minimal side effects. This study demonstrates that SAMe is safe to administer to patients ESRD.”

SESSION 18: ONE CARBON METABOLISM AND RELATED DISEASES IN MEDICAL PRACTICE

1. Vitamin B12 Deficiency in the Perinatal Period: Assessment, Consequences, Treatment and Prevention
LH Allen (California, United States)
“Adequate vitamin B12 status is critical in the perinatal period to enable normal pregnancy outcome and child development. Maternal repletion should occur pre-conception or as early in pregnancy as possible, because supplementation later in pregnancy and/or during lactation is unlikely to correct early maternal deficiency and prevent infant depletion.”

2. Vitamin use in correction of moderate and severe hyperhomocysteinemia
SP Stabler (Colorado, USA)
“There were only eight CBS deficient subjects in this cohort and the p.I278T mutation accounted for 50% of the mutations. There was a high prevalence of the MTHFRc.665TT genotype. The majority of those who had corrected tHcy were on high dose cobalamin.”

3. Hyperhomocysteinemia and cognitive impairment: causation or consequence?
A McCaddon (Wrexham, United Kingdom)
“Ultimate proof of causation requires human intervention studies; does correcting hyperhomocysteinemia prevent cognitive decline and/or incident dementia? Definitive trials in older adults experiencing cognitive decline are still urgently needed to fully resolve this issue.”

4. Predictors of maternal folate and vitamin B12 status among exclusively breastfeeding New Zealand women
RA Stamm (Dunedin, New Zealand)
“Compared with requirements, dietary intakes were low, particularly for folate. Supplement use during pregnancy and lactation is an important contributor to maternal folate and B12 status. Mothers of male infants may have a higher requirement for vitamin B12.”

5. One Carbon metabolism in young Indian girls: use of methionine load test
Prachi Katre (Pune, India)
“Supplementation of B12 deficient young girls with 2 mcg of B12/day for 6 months reduced hyperhomocysteinimia significantly, but did not normalize the levels. Multimicronuteints and protein had no additional effect. Dose-response and isotopic investigations will help study contribution of different metabolic cycles to deranged 1-C metabolism in this population.”