1  1939 151 EPIDEMIOLOGY AND (PATHO)PHYSIOLOGY OF FOLIC ACID SUPPLEMENT USE IN OBESE WOMEN BEFORE AND DURING PREGNANCY. PRECONCEPTION FOLIC ACID SUPPLEMENT USE IS A WELL-KNOWN METHOD OF PRIMARY PREVENTION OF NEURAL TUBE DEFECTS (NTDS). OBESE WOMEN ARE AT A HIGHER RISK FOR HAVING A CHILD WITH A NTD. AS DIFFERENT INTERNATIONAL RECOMMENDATIONS ON FOLIC ACID SUPPLEMENT USE FOR OBESE WOMEN BEFORE AND DURING PREGNANCY EXIST, THIS NARRATIVE REVIEW PROVIDES AN OVERVIEW OF EPIDEMIOLOGY OF FOLATE DEFICIENCY IN OBESE (PRE)PREGNANT WOMEN, ELABORATES ON POTENTIAL MECHANISMS UNDERLYING FOLATE DEFICIENCY, AND DISCUSSES CONSIDERATIONS FOR THE USAGE OF HIGHER DOSES OF FOLIC ACID SUPPLEMENTS. WOMEN WITH OBESITY MORE OFTEN SUFFER FROM AN ABSOLUTE FOLATE DEFICIENCY, AS THEY ARE LESS COMPLIANT TO PERICONCEPTIONAL FOLIC ACID SUPPLEMENT USE RECOMMENDATIONS. IN ADDITION, THEIR DIETARY FOLATE INTAKE IS LIMITED DUE TO AN UNBALANCED DIET (RELATIVE MALNUTRITION). THE ASSOCIATION OF OBESITY AND NTDS ALSO SEEMS TO BE INDEPENDENT OF FOLATE INTAKE, WITH STUDIES SUGGESTING AN INCREASED NEED OF FOLATE (RELATIVE DEFICIENCY) DUE TO DERANGEMENTS INVOLVED IN OTHER PATHWAYS. THE RELATIVE FOLATE DEFICIENCY, AS A RESULT OF AN INCREASED METABOLIC NEED FOR FOLATE IN OBESE WOMEN, CAN BE DUE TO: (1) LOW-GRADE CHRONIC INFLAMMATION (2) INSULIN RESISTANCE, (3) INOSITOL, AND (4) DYSBIOTIC GUT MICROBIOME, WHICH PLAYS A ROLE IN FOLATE PRODUCTION AND UPTAKE. IN ALL THESE PATHWAYS, THE FOLATE-DEPENDENT ONE-CARBON METABOLISM IS INVOLVED. IN CONCLUSION, SCIENTIFIC EVIDENCE OF THE INVOLVEMENT OF SEVERAL FOLATE-RELATED PATHWAYS IMPLIES TO INCREASE THE RECOMMENDED FOLIC ACID SUPPLEMENTATION IN OBESE WOMEN. HOWEVER, THE PHYSIOLOGICAL UPTAKE OF SYNTHETIC FOLIC ACID IS LIMITED AND SIDE-EFFECTS OF UNMETABOLIZED FOLIC ACID IN MOTHERS AND OFFSPRING, IN PARTICULAR VARIATIONS IN EPIGENETIC (RE)PROGRAMMING WITH LONG-TERM HEALTH EFFECTS, CANNOT BE EXCLUDED. THEREFORE, WE EMPHASIZE ON THE URGENT NEED FOR FURTHER RESEARCH AND PRECONCEPTION PERSONALIZED COUNSELING ON FOLATE STATUS, LIFESTYLE, AND MEDICAL CONDITIONS.	2021	
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 
2  4683  46 NEW PERSPECTIVES ON FOLATE TRANSPORT IN RELATION TO ALCOHOLISM-INDUCED FOLATE MALABSORPTION--ASSOCIATION WITH EPIGENOME STABILITY AND CANCER DEVELOPMENT. FOLATES ARE MEMBERS OF THE B-CLASS OF VITAMINS, WHICH ARE REQUIRED FOR THE SYNTHESIS OF PURINES AND PYRIMIDINES, AND FOR THE METHYLATION OF ESSENTIAL BIOLOGICAL SUBSTANCES, INCLUDING PHOSPHOLIPIDS, DNA, AND NEUROTRANSMITTERS. FOLATES CANNOT BE SYNTHESIZED DE NOVO BY MAMMALS; HENCE, AN EFFICIENT INTESTINAL ABSORPTION PROCESS IS REQUIRED. INTESTINAL FOLATE TRANSPORT IS CARRIER-MEDIATED, PH-DEPENDENT AND ELECTRONEUTRAL, WITH SIMILAR AFFINITY FOR OXIDIZED AND REDUCED FOLIC ACID DERIVATIVES. THE VARIOUS TRANSPORTERS, I.E. REDUCED FOLATE CARRIER, PROTON-COUPLED FOLATE TRANSPORTER, FOLATE-BINDING PROTEIN, AND ORGANIC ANION TRANSPORTERS, ARE INVOLVED IN THE FOLATE TRANSPORT PROCESS IN VARIOUS TISSUES. ANY IMPAIRMENT IN UPTAKE OF FOLATE CAN LEAD TO A STATE OF FOLATE DEFICIENCY, THE MOST PREVALENT VITAMIN DEFICIENCY IN WORLD, AFFECTING 10% OF THE POPULATION IN THE USA. SUCH IMPAIRMENTS IN FOLATE TRANSPORT OCCUR IN A VARIETY OF CONDITIONS, INCLUDING CHRONIC USE OF ETHANOL, SOME INBORN HEREDITARY DISORDERS, AND CERTAIN DISEASES. AMONG THESE, ETHANOL INGESTION HAS BEEN THE MAJOR CONTRIBUTOR TO FOLATE DEFICIENCY. ETHANOL-ASSOCIATED FOLATE DEFICIENCY CAN DEVELOP BECAUSE OF DIETARY INADEQUACY, INTESTINAL MALABSORPTION, ALTERED HEPATOBILIARY METABOLISM, ENHANCED COLONIC METABOLISM, AND INCREASED RENAL EXCRETION. ETHANOL REDUCES THE INTESTINAL AND RENAL UPTAKE OF FOLATE BY ALTERING THE BINDING AND TRANSPORT KINETICS OF FOLATE TRANSPORT SYSTEMS. ALSO, ETHANOL REDUCES THE EXPRESSION OF FOLATE TRANSPORTERS IN BOTH INTESTINE AND KIDNEY, AND THIS MIGHT BE A CONTRIBUTING FACTOR FOR FOLATE MALABSORPTION, LEADING TO FOLATE DEFICIENCY. THE MAINTENANCE OF INTRACELLULAR FOLATE HOMEOSTASIS IS ESSENTIAL FOR THE ONE-CARBON TRANSFER REACTIONS NECESSARY FOR DNA SYNTHESIS AND BIOLOGICAL METHYLATION REACTIONS. DNA METHYLATION IS AN IMPORTANT EPIGENETIC DETERMINANT IN GENE EXPRESSION, IN THE MAINTENANCE OF DNA INTEGRITY AND STABILITY, IN CHROMOSOMAL MODIFICATIONS, AND IN THE DEVELOPMENT OF MUTATIONS. ETHANOL, A TOXIN THAT IS CONSUMED REGULARLY, HAS BEEN FOUND TO AFFECT THE METHYLATION OF DNA. IN ADDITION TO ITS EFFECT ON DNA METHYLATION DUE TO FOLATE DEFICIENCY, ETHANOL COULD DIRECTLY EXERT ITS EFFECT THROUGH ITS INTERACTION WITH ONE-CARBON METABOLISM, IMPAIRMENT OF METHYL GROUP SYNTHESIS, AND AFFECTING THE ENZYMES REGULATING THE SYNTHESIS OF S-ADENOSYLMETHIONINE, THE PRIMARY METHYL GROUP DONOR FOR MOST BIOLOGICAL METHYLATION REACTIONS. THUS, ETHANOL PLAYS AN IMPORTANT ROLE IN THE PATHOGENESIS OF SEVERAL DISEASES THROUGH ITS POTENTIAL ABILITY TO MODULATE THE METHYLATION OF BIOLOGICAL MOLECULES. THIS REVIEW DISCUSSES THE UNDERLYING MECHANISM OF FOLATE MALABSORPTION IN ALCOHOLISM, THE MECHANISM OF METHYLATION-ASSOCIATED SILENCING OF GENES, AND HOW THE INTERACTION BETWEEN ETHANOL AND FOLATE DEFICIENCY AFFECTS THE METHYLATION OF GENES, THEREBY MODULATING EPIGENOME STABILITY AND THE RISK OF CANCER.	2009	

3  4251  42 METHYLENETETRAHYDROFOLATE REDUCTASE (MTHFR) GENE POLYMORPHISMS RESULTING IN SUBOPTIMAL OOCYTE MATURATION: A DISCUSSION OF FOLATE STATUS, NEURAL TUBE DEFECTS, SCHIZOPHRENIA, AND VASCULOPATHY. SEVERAL CONDITIONS APPARENT AT BIRTH, E.G., NEURAL TUBE DEFECTS (NTDS) AND CARDIAC ANOMALIES, ARE ASSOCIATED WITH POLYMORPHISMS IN FOLATE-RELATED GENES, SUCH AS THE 677C --> T POLYMORPHISM OF THE METHYLENETETRAHYDROFOLATE REDUCTASE (MTHFR) GENE. SIMILAR ASSOCIATIONS HAVE BEEN ESTABLISHED FOR SEVERAL CONSTITUTIONAL CHRONIC DISEASES IN ADULTHOOD, SUCH AS SCHIZOPHRENIA, CARDIOVASCULAR DISEASES, DEMENTIA, AND EVEN NEOPLASIAS IN DIFFERENT ORGAN SYSTEMS. THIS SPECTRUM OF DEVELOPMENTAL ANOMALIES AND CONSTITUTIONAL DISEASES MAY BE LINKED TO HIGH-RISK CONCEPTIONS RELATED TO PREOVULATORY OVERRIPENESS OVOPATHY (PROO). SOME DEVELOPMENTAL ANOMALIES, SUCH AS NTDS, ARE TO A LARGE EXTENT PREVENTED BY SUPPLEMENTATION OF FOLIC ACID BEFORE CONCEPTION, BUT SUPPLEMENTATION DOES NOT SEEM TO PREVENT CARDIOVASCULAR DISEASE OR COGNITIVE DECLINE. THESE DIVERGING RESULTS CAN BE ELUCIDATED BY INTRODUCTION OF THE PROO CONCEPT, AS MTHFR POLYMORPHISMS AND INHERENT LOW FOLATE LEVELS INDUCE BOTH NON-OPTIMAL MATURATION OF THE OOCYTE AND UNSUCCESSFUL DNA METHYLATION AND DEMETHYLATION, I.E. EPIGENETIC MUTATIONS. THE PROO CONCEPT IS TESTABLE AND PREDICTS IN A RANDOM POPULATION THE FOLLOWING: (1) FEMALE CARRIERS OF SPECIFIC GENETIC MTHFR VARIANTS EXHIBIT MORE OVULATORY DISTURBANCES AND INHERENT SUBFECUNDITY TRAITS, (2) DESCENDENTS FROM A CARRIER MOTHER, WHEN COMPARED WITH THOSE FROM A WILD-TYPE MOTHER, ARE MORE FREQUENTLY CONCEIVED IN PROO HIGH-RISK CONDITIONS AND, THUS, (3) DISADVANTAGED IN LIFE EXPECTANCY. IF SO, SOME MTHFR POLYMORPHISMS REPRESENT A NOVEL, GENETICALLY DETERMINED, PROO HIGH-RISK CONCEPTION CATEGORY COMPARABLE TO THOSE WHICH ARE ENVIRONMENTALLY AND BEHAVIORLY INFLUENCED. THESE HIGH-RISK CONDITIONS MAY CAUSE DEVELOPMENTAL ANOMALIES AND DEFECTIVE EPIGENETIC REPROGRAMMING IN PROGENY. THE INTERACTION BETWEEN GENETIC AND ENVIRONMENTAL FACTORS IS A PLAUSIBLE MECHANISM OF MULTIFACTORIAL INHERITANCE.	2008	
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        
4  2995  34 GENETIC POLYMORPHISMS IN FOLATE PATHWAY ENZYMES, DRD4 AND GSTM1 ARE RELATED TO TEMPOROMANDIBULAR DISORDER. BACKGROUND: TEMPOROMANDIBULAR DISORDER (TMD) IS A MULTIFACTORIAL SYNDROME RELATED TO A CRITICAL PERIOD OF HUMAN LIFE. TMD HAS BEEN ASSOCIATED WITH PSYCHOLOGICAL DYSFUNCTIONS, OXIDATIVE STATE AND SEXUAL DIMORPHISM WITH COINCIDENTAL OCCURRENCE ALONG THE PUBERTAL DEVELOPMENT. IN THIS WORK WE STUDY THE ASSOCIATION BETWEEN TMD AND GENETIC POLYMORPHISMS OF FOLATE METABOLISM, NEUROTRANSMISSION, OXIDATIVE AND HORMONAL METABOLISM. FOLATE METABOLISM, WHICH DEPENDS ON GENES VARIATIONS AND DIET, IS DIRECTLY INVOLVED IN GENETIC AND EPIGENETIC VARIATIONS THAT CAN INFLUENCE THE CHANGES OF LAST GROWING PERIOD OF DEVELOPMENT IN HUMAN AND THE APPEARANCE OF THE TMD. METHODS: A CASE-CONTROL STUDY WAS DESIGNED TO EVALUATE THE IMPACT OF GENETIC POLYMORPHISMS ABOVE DESCRIBED ON TMD. A TOTAL OF 229 INDIVIDUALS (69% WOMEN) WERE INCLUDED AT THE STUDY; 86 WERE PATIENTS WITH TMD AND 143 WERE HEALTHY CONTROL SUBJECTS. SUBJECTS UNDERWENT TO A CLINICAL EXAMINATION FOLLOWING THE GUIDELINES BY THE RESEARCH DIAGNOSTIC CRITERIA FOR TEMPOROMANDIBULAR DISORDERS (RDC/TMD). GENOTYPING OF 20 SINGLE NUCLEOTIDE POLYMORPHISMS (SNPS), DIVIDED IN TWO GROUPS, WAS PERFORMED BY MULTIPLEX MINISEQUENCING PRECEDED BY MULTIPLEX PCR. OTHER SEVEN GENETIC POLYMORPHISMS DIFFERENT FROM SNPS (DELETIONS, INSERTIONS, TANDEM REPEAT, NULL GENOTYPE) WERE ACHIEVED BY A MULTIPLEX-PCR. A CHI-SQUARE TEST WAS PERFORMED TO DETERMINE THE DIFFERENCES IN GENOTYPE AND ALLELIC FREQUENCIES BETWEEN TMD PATIENTS AND HEALTHY SUBJECTS. TO ESTIMATE TMD RISK, IN THOSE POLYMORPHISMS THAT SHOWN SIGNIFICANT DIFFERENCES, ODDS RATIO (OR) WITH A 95% OF CONFIDENCE INTERVAL WERE CALCULATED. RESULTS: SIX OF THE POLYMORPHISMS SHOWED STATISTICAL ASSOCIATIONS WITH TMD. FOUR OF THEM ARE RELATED TO ENZYMES OF FOLATES METABOLISM: ALLELE G OF SERINE HYDOXYMETHYLTRANSFERASE 1 (SHMT1) RS1979277 (OR = 3.99; 95%CI 1.72, 9.25; P = 0.002), ALLELE G OF SHMT1 RS638416 (OR = 2.80; 95%CI 1.51, 5.21; P = 0.013), ALLELE T OF METHYLENTETRAHYDROFOLATE DEHYDROGENASE (MTHFD) RS2236225 (OR = 3.09; 95%CI 1.27, 7.50; P = 0.016) AND ALLELE A OF METHIONINE SYNTHASE REDUCTASE (MTRR) RS1801394 (OR = 2.35; 95CI 1.10, 5.00; P = 0.037). AN INFLAMMATORY OXIDATIVE STRESS ENZYME, GLUTHATIONE S-TRANFERASE MU-1(GSTM1), NULL ALLELE (OR = 2.21; 95%CI 1.24, 4.36; P = 0.030) AND A NEUROTRANSMISSION RECEPTOR, DOPAMINE RECEPTOR D4 (DRD4), LONG ALLELE OF 48 BP-REPEAT (OR = 3.62; 95%CI 0.76, 17.26; P = 0.161). CONCLUSIONS: SOME GENETIC POLYMORPHISMS RELATED TO FOLATES METABOLISM, INFLAMMATORY OXIDATIVE STRESS, AND NEUROTRANSMISSION RESPONSES TO PAIN, HAS BEEN SIGNIFICANTLY ASSOCIATED TO TMD SYNDROME.	2011	
                                                                                                                                                                                                                                                                                                                                                       
5  5904  29 T677T METHYLENETETRAHYDROFOLATE REDUCTASE SINGLE NUCLEOTIDE POLYMORPHISMS INCREASED PREVALENCE IN A SUBGROUP OF INFERTILE PATIENTS WITH ENDOMETRIOSIS. BACKGROUND: APPROXIMATELY 10% (190 MILLION) OF WOMEN WORLDWIDE ARE AFFECTED BY ENDOMETRIOSIS, ECTOPIC DEPOSITS OF ENDOMETRIAL TISSUE THAT CREATE A MAJOR SOURCE OF PAIN THAT AFFECTS LIFESTYLE AND REPRODUCTIVE FUNCTION. THE PATHOGENESIS OF ENDOMETRIOSIS IS AN ESTROGEN-DEPENDENT INFLAMMATORY PROCESS, INFLUENCED/CATALYZED BY OXIDATIVE STRESS AND CONSEQUENTLY DEFECTIVE METHYLATION, WITH BIOCHEMICAL FEATURES CENTERED AROUND THE FOLATE AND ONE-CARBON CYCLES. WE AIMED TO DETERMINE WHETHER A LINK COULD BE FOUND BETWEEN THE TWO MAJOR METHYLENETETRAHYDROFOLATE REDUCTASE SINGLE NUCLEOTIDE POLYMORPHISMS (MTHFR SNPS), C.677C>T AND C.1298A>C, INVOLVED IN METHYLATION PROCESS/EPIGENETIC MARKING FAILURES, AND ENDOMETRIOSIS. MATERIAL AND METHODS: WE STUDIED A POPULATION OF 158 PATIENTS IN A GROUP OF >1500 REFERRED FOR TREATMENT OF INFERTILITY. ALL THE PATIENTS HAD EXPERIENCED >2 FAILED ASSISTED REPRODUCTIVE TECHNOLOGY CYCLES AND/OR >2 MISCARRIAGES, A CLASSICAL COHORT FOR INVESTIGATION IN OUR GROUP. PATIENTS WITH ENDOMETRIOSIS HAD AT LEAST STAGE 2+ DISEASE CONFIRMED BY LAPAROSCOPY. RESULTS: THE PREVALENCE OF THE HOMOZYGOUS C.677C>T ISOFORM IS DOUBLED IN THE ENDOMETRIOSIS GROUP, 21.5% VERSUS 10.2% IN THE NON-ENDOMETRIOSIS GROUP (P > 0.01). SYMMETRICALLY, THE PERCENTAGE OF PATIENTS IN THE ENDOMETRIOSIS GROUP WITH THE WILD TYPE MTHFR SIGNIFICANTLY DECREASED BY ONE-HALF (8.2%-17.2%) IN THE NON-ENDOMETRIOSIS GROUP (P < 0.001). CONCLUSION: DETERMINATION OF MTHFR C.677C>T SHOULD NOT BE OVERLOOKED IN PATIENTS WITH HARMFUL ENDOMETRIOSIS AFFECTING THEIR FERTILITY. AS FOLATES METABOLISM IS IMPAIRED IN THESE MTHFR SNPS CARRIER PATIENTS, CO-TREATMENT WITH 5-METHYL FOLATE MAY CONSTITUTE A SUCCESSFUL (CO)-TREATMENT MODALITY.	2022	
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         
6  4011  33 LOW PATERNAL DIETARY FOLATE ALTERS THE MOUSE SPERM EPIGENOME AND IS ASSOCIATED WITH NEGATIVE PREGNANCY OUTCOMES. EPIDEMIOLOGICAL STUDIES SUGGEST THAT A FATHER'S DIET CAN INFLUENCE OFFSPRING HEALTH. A PROPOSED MECHANISM FOR PATERNAL TRANSMISSION OF ENVIRONMENTAL INFORMATION IS VIA THE SPERM EPIGENOME. THE EPIGENOME INCLUDES HERITABLE INFORMATION SUCH AS DNA METHYLATION. WE HYPOTHESIZE THAT THE DIETARY SUPPLY OF METHYL DONORS WILL ALTER EPIGENETIC REPROGRAMMING IN SPERM. HERE WE FEED MALE MICE EITHER A FOLATE-DEFICIENT OR FOLATE-SUFFICIENT DIET THROUGHOUT LIFE. PATERNAL FOLATE DEFICIENCY IS ASSOCIATED WITH INCREASED BIRTH DEFECTS IN THE OFFSPRING, WHICH INCLUDE CRANIOFACIAL AND MUSCULOSKELETAL MALFORMATIONS. GENOME-WIDE DNA METHYLATION ANALYSIS AND THE SUBSEQUENT FUNCTIONAL ANALYSIS IDENTIFY DIFFERENTIAL METHYLATION IN SPERM OF GENES IMPLICATED IN DEVELOPMENT, CHRONIC DISEASES SUCH AS CANCER, DIABETES, AUTISM AND SCHIZOPHRENIA. WHILE >300 GENES ARE DIFFERENTIALLY EXPRESSED IN OFFSPRING PLACENTA, ONLY TWO CORRESPOND TO GENES WITH DIFFERENTIAL METHYLATION IN SPERM. THIS MODEL SUGGESTS EPIGENETIC TRANSMISSION MAY INVOLVE SPERM HISTONE H3 METHYLATION OR DNA METHYLATION AND THAT ADEQUATE PATERNAL DIETARY FOLATE IS ESSENTIAL FOR OFFSPRING HEALTH.	2013	
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             
7  6305  48 THE QUESTION IS WHETHER INTAKE OF FOLIC ACID FROM DIET ALONE DURING PREGNANCY IS SUFFICIENT. PREGNANCY AND FOLIC ACID: PREGNANCY IS THE MOST IMPORTANT PERIOD IN LIFE OF EVERY WOMAN, PARTIALLY FOR THE NUMBER OF PHYSIOLOGICAL ADAPTATIONS SHE IS GOING THROUGH, PARTIALLY FOR THE EXPECTANCE OF NEW LIFE. IN ADDITION, PREGNANCY IS THE "CRITICAL WINDOW" FOR DEVELOPMENT LATER IN CHILDHOOD, AS A PERIOD OF FOETAL PROGRAMMING DURING WHICH NUTRITION PLAYS ONE OF CRUCIAL ROLES. DESPITE THE GENERAL BELIEF THAT NUTRITION THROUGH PREGNANCY IS ADEQUATE AND CHARACTERIZED BY BETTER NUTRITIONAL HABITS, A NUMBER OF STUDIES DO NOT CORROBORATE THIS BELIEF. ROLE OF FOLIC ACID: AN ADEQUATE FOLATE BLOOD LEVEL IS NECESSARY FOR NORMAL CELL GROWTH, SYNTHESIS OF SEVERAL COMPOUNDS INCLUDING DEOXYRIBONUCLEIC ACID AND RIBONUCLEIC ACID, PROPER BRAIN AND NEUROLOGIC FUNCTIONS; IT IS INCLUDED IN THE REGULATION OF HOMOCYSTEINE LEVEL, AND CLOSELY RELATED TO THE VITAMIN B12 METABOLISM. FOLATE DEFICIENCY IN PREGNANCY IS RELATED TO NEURAL TUBE DEFECTS, OTHER NEUROLOGICAL DISORDERS, PRETERM DELIVERY AND LOW BIRTH WEIGHT. FOOD SOURCES: A CORRELATION BETWEEN FOLATE AND THE PREVENTION OF BROAD SPECTRUM OF CHRONIC DISEASES HAS BEEN CONFIRMED. EMERGING EVIDENCE FROM THE EPIGENETIC STUDIES IS NOW BRINGING EVEN MORE LIGHT ON THE LEVEL OF SIGNIFICANCE OF FOLIC ACID. A WIDE RANGE OF PLANT AND ANIMAL FOODS ARE THE NATURAL SOURCES OF FOLATE; LIVER, YEAST, MUSHROOMS, AND GREEN LEAFY VEGETABLES BEING THE MOST SIGNIFICANT. DIFFERENT WAYS OF FOOD PREPARATION INFLUENCE THE FOLATE STABILITY AND ITS BIOAVAILABILITY VARIES FROM 25 TO 50% FROM FOODS, 85% FROM ENRICHED FOODS OR 100% FROM SUPPLEMENTS. CONCLUSION: A GREAT AMOUNT OF SCIENTIFIC RESULTS HAS LED TO OFFICIAL RECOMMENDATIONS FOR FOLIC ACID SUPPLEMENTATION IN PREGNANT WOMEN AS WELL AS IN A NUMBER OF OBLIGATORY OR VOLUNTARY FORTIFICATION PROGRAMMES IN ORDER TO PREVENT THE FOLATE DEFICIENCY ON THE LEVEL OF DIFFERENT POPULATION GROUPS. NEVERTHELESS, THERE MUST BE A CERTAIN LEVEL OF PRECAUTION FOR ELDERLY BECAUSE FOLATE CAN MASK THE VITAMIN B12 DEFICIENCY WITH POSSIBLE FATAL OUTCOMES.	2014	
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        
8  4086  33 MATERNAL OBESITY DISRUPTS THE METHIONINE CYCLE IN BABOON PREGNANCY. MATERNAL INTAKE OF DIETARY METHYL-MICRONUTRIENTS (E.G. FOLATE, CHOLINE, BETAINE AND VITAMIN B-12) DURING PREGNANCY IS ESSENTIAL FOR NORMAL MATERNAL AND FETAL METHIONINE METABOLISM, AND IS CRITICAL FOR IMPORTANT METABOLIC PROCESSES INCLUDING THOSE INVOLVED IN DEVELOPMENTAL PROGRAMMING. MATERNAL OBESITY AND NUTRIENT EXCESS DURING PREGNANCY INFLUENCE DEVELOPMENTAL PROGRAMMING POTENTIALLY PREDISPOSING ADULT OFFSPRING TO A VARIETY OF CHRONIC HEALTH PROBLEMS. IN THE PRESENT STUDY, WE HYPOTHESIZED THAT MATERNAL OBESITY WOULD DYSREGULATE THE MATERNAL AND FETAL METHIONINE CYCLE. TO TEST THIS HYPOTHESIS, WE DEVELOPED A NULLIPAROUS BABOON OBESITY MODEL FED A HIGH FAT, HIGH ENERGY DIET (HF-HED) PRIOR TO AND DURING GESTATION, AND EXAMINED METHIONINE CYCLE BIOMARKERS (E.G., CIRCULATING CONCENTRATIONS OF HOMOCYSTEINE, METHIONINE, CHOLINE, BETAINE, KEY AMINO ACIDS, FOLATE, AND VITAMIN B-12). ANIMALS WERE GROUP HOUSED ALLOWING FULL PHYSICAL ACTIVITY AND SOCIAL INTERACTION. MATERNAL PREPREGNANCY PERCENT BODY FAT WAS 5% IN CONTROLS AND 19% IN HF-HED MOTHERS, WHILE FETAL WEIGHT WAS 16% LOWER IN OFFSPRING OF HF-HED MOTHERS AT TERM. MATERNAL AND FETAL HOMOCYSTEINE WERE HIGHER, WHILE MATERNAL AND FETAL VITAMIN B-12 AND BETAINE WERE LOWER IN THE HF-HED GROUP. ELEVATIONS IN CIRCULATING MATERNAL FOLATE WERE EVIDENT IN THE HF-HED GROUP INDICATING IMPAIRED FOLATE METABOLISM (METHYL-TRAP) AS A CONSEQUENCE OF MATERNAL VITAMIN B-12 DEPLETION. FINALLY, FETAL METHIONINE, GLYCINE, SERINE, AND TAURINE WERE LOWER IN THE HF-HED FETUSES. THESE DATA SHOW THAT MATERNAL OBESITY DISTURBS THE METHIONINE CYCLE IN PRIMATE PREGNANCY, PROVIDING A MECHANISM FOR THE EPIGENETIC CHANGES OBSERVED AMONG OBESE PREGNANT WOMEN AND SUGGESTING DIAGNOSTIC AND THERAPEUTIC OPPORTUNITIES IN HUMAN PREGNANCIES COMPLICATED BY OBESITY.	2015	
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          
9  4214  38 METHIONINE METABOLISM IN YUCATAN MINIATURE SWINE. METHIONINE IS AN ESSENTIAL AMINO ACID WHICH WHEN NOT INCORPORATED INTO PROTEIN, CAN BE CONVERTED TO S-ADENOSYLMETHIONINE, THE UNIVERSAL METHYL DONOR IN OVER 200 TRANSMETHYLATION REACTIONS, WHICH INCLUDE CREATINE AND PHOSPHATIDYLCHOLINE (PC) SYNTHESIS, AS WELL AS DEOXYRIBONUCLEIC ACID (DNA) METHYLATION. FOLLOWING TRANSMETHYLATION, HOMOCYSTEINE IS FORMED, WHICH CAN BE CONVERTED TO CYSTEINE VIA TRANSSULFURATION OR REMETHYLATED TO METHIONINE BY RECEIVING A METHYL GROUP FROM FOLATE OR BETAINE. CHANGES TO METHYL GROUP AVAILABILITY IN UTERO CAN LEAD TO PERMANENT CHANGES IN EPIGENETIC PATTERNS OF DNA METHYLATION, WHICH HAS BEEN IMPLICATED IN "FETAL PROGRAMMING", A PHENOMENON ASSOCIATED WITH POOR NUTRITION DURING FETAL DEVELOPMENT THAT RESULTS IN LOW BIRTH WEIGHT AND DISEASE IN LATER LIFE. IT HAS BEEN SHOWN THAT PROGRAMMING CAN ALSO OCCUR IN THE NEONATE. OUR GLOBAL OBJECTIVE WAS TO UNDERSTAND HOW THE VARIABILITY OF NUTRIENTS INVOLVED IN METHIONINE METABOLISM CAN AFFECT METHIONINE AND METHYL GROUP AVAILABILITY. WE HYPOTHESIZE THAT NUTRIENTS THAT CONVERGE ON METHIONINE METABOLISM CAN AFFECT METHIONINE AVAILABILITY FOR ITS VARIOUS FUNCTIONS. IN THIS THESIS, WE USED INTRAUTERINE GROWTH RESTRICTED (IUGR) PIGLETS TO INVESTIGATE WHETHER A GLOBAL NUTRITIONAL INSULT IN UTERO CAN LEAD TO A PERTURBED METHIONINE METABOLISM. OUR RESULTS DEMONSTRATE THAT IUGR PIGLETS HAVE A LOWER CAPACITY TO DISPOSE OF HOMOCYSTEINE VIA BOTH TRANSSULFURATION AND REMETHYLATION PATHWAYS, AS WELL AS A LOWER INCORPORATION OF METHYL GROUPS INTO PC. THE SECOND OBJECTIVE OF THIS THESIS WAS TO DETERMINE WHETHER VARIATION IN METHIONINE SUPPLY AND DEMAND CAN AFFECT METHIONINE AVAILABILITY. WE DEMONSTRATED THAT STIMULATING EITHER ACUTE OR CHRONIC CREATINE SYNTHESIS LEADS TO LOWER METHYL INCORPORATION INTO PROTEIN AND PC IN PIGS. FURTHERMORE, WHEN METHIONINE IS LIMITING, SUPPLEMENTATION WITH EITHER FOLATE OR BETAINE LEADS TO HIGHER METHIONINE AVAILABILITY FOR PROTEIN SYNTHESIS. FINALLY, BECAUSE CREATINE IS INCREASINGLY BEING UTILIZED AS AN ERGOGENIC AND NEUROPROTECTIVE SUPPLEMENT, WE WANTED TO DETERMINE WHETHER PROVISION OF THE CREATINE PRECURSOR, GUANIDINOACETATE (GAA), COULD EFFECTIVELY INCREASE TISSUE CREATINE STORES. WE SHOWED THAT 2.5 WEEKS OF SUPPLEMENTATION WITH GAA IS MORE EFFECTIVE THAN CREATINE AT INCREASING HEPATIC AND MUSCLE CREATINE STORES. THE RESULTS OF THIS THESIS DEMONSTRATE THAT THE PRESENCE OF IUGR, AN INCREASED DEMAND FOR CREATINE SYNTHESIS, OR THE SUPPLEMENTATION WITH REMETHYLATION NUTRIENTS CAN EACH AFFECT METHIONINE AVAILABILITY; ALL ARE IMPORTANT WHEN CONSIDERING NEONATAL NUTRIENT REQUIREMENTS. FURTHERMORE, ALTHOUGH GAA IS EFFECTIVE AT INCREASING LEVELS OF TISSUE CREATINE, HIGHER GAA METHYLATION CAN LIMIT METHIONINE AVAILABILITY FOR GROWTH AND SYNTHESIS OF PC.	2016	
                                                                                                                                                                                                                                        
10  2833  27 FOLATE AND DNA METHYLATION: A REVIEW OF MOLECULAR MECHANISMS AND THE EVIDENCE FOR FOLATE'S ROLE. DNA METHYLATION IS AN EPIGENETIC MODIFICATION CRITICAL TO NORMAL GENOME REGULATION AND DEVELOPMENT. THE VITAMIN FOLATE IS A KEY SOURCE OF THE ONE CARBON GROUP USED TO METHYLATE DNA. BECAUSE NORMAL MAMMALIAN DEVELOPMENT IS DEPENDENT ON DNA METHYLATION, THERE IS ENORMOUS INTEREST IN ASSESSING THE POTENTIAL FOR CHANGES IN FOLATE INTAKE TO MODULATE DNA METHYLATION BOTH AS A BIOMARKER FOR FOLATE STATUS AND AS A MECHANISTIC LINK TO DEVELOPMENTAL DISORDERS AND CHRONIC DISEASES INCLUDING CANCER. THIS REVIEW HIGHLIGHTS THE ROLE OF DNA METHYLATION IN NORMAL GENOME FUNCTION, HOW IT CAN BE ALTERED, AND THE EVIDENCE OF THE ROLE OF FOLATE/FOLIC ACID IN THESE PROCESSES.	2012	
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              
11   558  33 B-VITAMIN DEPENDENT METHIONINE METABOLISM AND ALCOHOLIC LIVER DISEASE. CONVINCING EVIDENCE LINKS ABERRANT B-VITAMIN DEPENDENT HEPATIC METHIONINE METABOLISM TO THE PATHOGENESIS OF ALCOHOLIC LIVER DISEASE (ALD). THIS REVIEW FOCUSES ON THE ESSENTIAL ROLES OF FOLATE AND VITAMINS B6 AND B12 IN HEPATIC METHIONINE METABOLISM, THE CAUSES OF THEIR DEFICIENCIES AMONG CHRONIC ALCOHOLIC PERSONS, AND HOW THEIR DEFICIENCIES TOGETHER WITH CHRONIC ALCOHOL EXPOSURE IMPACT ON ABERRANT METHIONINE METABOLISM IN THE PATHOGENESIS OF ALD. FOLATE IS THE DIETARY TRANSMETHYLATION DONOR FOR THE PRODUCTION OF S-ADENOSYLMETHIONINE (SAM), WHICH IS THE SUBSTRATE FOR ALL METHYLTRANSFERASES THAT REGULATE GENE EXPRESSIONS IN PATHWAYS OF LIVER INJURY, AS WELL AS A REGULATOR OF THE TRANSSULFURATION PATHWAY THAT IS ESSENTIAL FOR PRODUCTION OF GLUTATHIONE (GSH), THE PRINCIPAL ANTIOXIDANT FOR DEFENSE AGAINST OXIDATIVE LIVER INJURY. VITAMIN B12 REGULATES TRANSMETHYLATION REACTIONS FOR SAM PRODUCTION AND VITAMIN B6 REGULATES TRANSSULFURATION REACTIONS FOR GSH PRODUCTION. FOLATE DEFICIENCY ACCELERATES THE EXPERIMENTAL DEVELOPMENT OF ALD IN ETHANOL-FED ANIMALS WHILE REDUCING LIVER SAM LEVELS WITH RESULTANT ABNORMAL GENE EXPRESSION AND DECREASED PRODUCTION OF ANTIOXIDANT GSH. THROUGH ITS EFFECTS ON FOLATE METABOLISM, REDUCED SAM ALSO IMPAIRS NUCLEOTIDE BALANCE WITH RESULTANT INCREASED DNA STRAND BREAKS, OXIDATION, HEPATOCELLULAR APOPTOSIS, AND RISK OF CARCINOGENESIS. THE REVIEW ENCOMPASSES REFERENCED STUDIES ON MECHANISMS FOR PERTURBATIONS OF METHIONINE METABOLISM IN ALD, EVIDENCE FOR ALTERED GENE EXPRESSIONS AND THEIR EPIGENETIC REGULATION IN THE PATHOGENESIS OF ALD, AND CLINICAL STUDIES ON POTENTIAL PREVENTION AND TREATMENT OF ALD BY CORRECTION OF METHIONINE METABOLISM WITH SAM.	2013	
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               
12  4069  32 MATERNAL CHRONIC FOLATE SUPPLEMENTATION AMELIORATES BEHAVIOR DISORDERS INDUCED BY PRENATAL HIGH-FAT DIET THROUGH METHYLATION ALTERATION OF BDNF AND GRIN2B IN OFFSPRING HIPPOCAMPUS. SCOPE: MATERNAL CONSUMPTION OF A HIGH-FAT DIET (HFD) DURING PREGNANCY INCREASES THE RISK OF BEHAVIORAL PROBLEMS. FOLATE PLAYS AN IMPORTANT ROLE IN NEUROPLASTICITY AND THE PRESERVATION OF NEURONAL INTEGRITY. THIS STUDY AIMS AT DETERMINING THE INFLUENCE OF DIETS SUPPLEMENTED WITH FOLATE ON OFFSPRING BEHAVIOR, AND THE MECHANISMS INVOLVED. METHODS AND RESULTS: FEMALE MICE WERE FED A CONTROL DIET, AN HFD, CONTROL DIET SUPPLEMENTED WITH FOLATE, OR AN HFD SUPPLEMENTED WITH FOLATE FOR 5 WEEKS BEFORE MATING. OPEN FIELD TASK AND ELEVATED PLUS MAZE ARE USED TO EVALUATE THE OFFSPRING BEHAVIORS. RESULTS SHOWED THAT OFFSPRING COGNITIVE PERFORMANCE AND ANXIETY-RELATED BEHAVIORS, INCLUDING THOSE RELATED TO OPEN FIELD EXPLORATION AND ELEVATED PLUS MAZE, WERE SIGNIFICANTLY IMPROVED WHEN DAMS WERE TREATED WITH FOLATE IN PREGNANCY. MOREOVER, THE MATERNAL FOLATE SUPPLEMENT DECREASED BDNF AND GRIN2B METHYLATION AND UPREGULATED THEIR EXPRESSIONS IN THE BRAIN OF OFFSPRING, WHICH WERE ASSOCIATED WITH DECREASING THE EXPRESSION OF DNA METHYLTRANSFERASES COMPARED WITH THOSE DAMS WERE TREATED ONLY HFD IN PREGNANCY. CONCLUSION: MATERNAL FOLATE SUPPLEMENTATION AMELIORATES BEHAVIOR DISORDERS INDUCED BY PRENATAL HIGH-FAT DIET. THE BENEFICIAL EFFECTS WERE ASSOCIATED WITH METHYLATION AND EXPRESSION ALTERATION OF BDNF AND GRIN2B GENES.	2017	
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        
13    48  32 A CRUCIAL ROLE FOR MATERNAL DIETARY METHYL DONOR INTAKE IN EPIGENETIC PROGRAMMING AND FETAL GROWTH OUTCOMES. THE FETAL ORIGINS OF HEALTH AND DISEASE FRAMEWORK HAS IDENTIFIED EXTREMES IN FETAL GROWTH AND BIRTH WEIGHT AS FACTORS ASSOCIATED WITH THE LIFELONG GENERATION OF CHRONIC DISEASES SUCH AS OBESITY, DIABETES, CARDIOVASCULAR DISEASE, AND HYPERTENSION. MATERNAL NUTRITION PLAYS A CRITICAL ROLE IN FETAL AND PLACENTAL DEVELOPMENT, IN PART BY PROVIDING THE METHYL GROUPS REQUIRED TO ESTABLISH THE FETUS'S GENOME STRUCTURE AND FUNCTION, NOTABLY THROUGH DNA METHYLATION. THE GOAL OF THIS NARRATIVE REVIEW IS TO DESCRIBE THE ROLE OF MATERNAL DIETARY METHYL DONOR (METHIONINE, FOLATE, AND CHOLINE) AND COFACTOR (ZINC AND VITAMINS B2, B6, AND B12) INTAKE IN ONE-CARBON METABOLISM AND DNA METHYLATION IN THE FETUS AND PLACENTA, AS WELL AS THEIR IMPACTS ON FETAL GROWTH AND LIFELONG HEALTH OUTCOMES, WITH SPECIFIC EXAMPLES IN ANIMALS AND HUMANS. BASED ON THE AVAILABLE EVIDENCE, IT IS CONCLUDED THAT INTAKE OF DIFFERENT AMOUNTS OF DIETARY METHYL DONORS AND COFACTORS DURING PREGNANCY MAY ALTER FETAL GROWTH AND DEVELOPMENT, THUS ESTABLISHING A MAJOR LINK BETWEEN EARLY ENVIRONMENTAL EXPOSURE AND DISEASE DEVELOPMENT IN THE OFFSPRING LATER IN LIFE.	2018	
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             
14   853  24 CHOLINE, OTHER METHYL-DONORS AND EPIGENETICS. CHOLINE DIETARY INTAKE VARIES SUCH THAT MANY PEOPLE DO NOT ACHIEVE ADEQUATE INTAKES. DIET INTAKE OF CHOLINE CAN MODULATE METHYLATION BECAUSE, VIA BETAINE HOMOCYSTEINE METHYLTRANSFERASE (BHMT), THIS NUTRIENT (AND ITS METABOLITE, BETAINE) REGULATE THE CONCENTRATIONS OF S-ADENOSYLHOMOCYSTEINE AND S-ADENOSYLMETHIONINE. SOME OF THE EPIGENETIC MECHANISMS THAT MODIFY GENE EXPRESSION WITHOUT MODIFYING THE GENETIC CODE DEPEND ON THE METHYLATION OF DNA OR OF HISTONES; AND DIET AVAILABILITY OF CHOLINE AND OTHER METHYL-GROUP DONORS INFLUENCES BOTH OF THESE METHYLATIONS. EXAMPLES OF METHYL-DONOR MEDIATED EPIGENETIC EFFECTS INCLUDE THE CHANGES IN COAT COLOR AND BODY WEIGHT IN OFFSPRING WHEN PREGNANT AGOUTI MICE ARE FED HIGH CHOLINE, HIGH METHYL DIETS; THE CHANGES IN TAIL KINKING IN OFFSPRING WHEN PREGNANT AXIN(FU) MICE ARE FED HIGH CHOLINE, HIGH METHYL DIETS; THE CHANGES IN CDKN3 METHYLATION AND ALTERED BRAIN DEVELOPMENT THAT OCCURS IN OFFSPRING WHEN PREGNANT RODENTS ARE FED LOW CHOLINE DIETS. WHEN CHOLINE METABOLISM IS DISRUPTED BY DELETING THE GENE BHMT, DNA METHYLATION IS AFFECTED (ESPECIALLY IN A REGION OF CHROMOSOME 13), EXPRESSION OF SPECIFIC GENES IS SUPPRESSED, AND LIVER CANCERS DEVELOP. BETTER UNDERSTANDING OF HOW NUTRIENTS SUCH AS CHOLINE AND METHYL-DONORS INFLUENCE EPIGENETIC PROGRAMS HAS IMPORTANCE FOR OUR UNDERSTANDING OF NOT ONLY DEVELOPMENTAL ABNORMALITIES BUT ALSO FOR UNDERSTANDING THE ORIGINS OF CHRONIC DISEASES.	2017	
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         
15  1855  28 ELEVATION IN S-ADENOSYLHOMOCYSTEINE AND DNA HYPOMETHYLATION: POTENTIAL EPIGENETIC MECHANISM FOR HOMOCYSTEINE-RELATED PATHOLOGY. CHRONIC NUTRITIONAL DEFICIENCIES IN FOLATE, CHOLINE, METHIONINE, VITAMIN B-6 AND/OR VITAMIN B-12 CAN PERTURB THE COMPLEX REGULATORY NETWORK THAT MAINTAINS NORMAL ONE-CARBON METABOLISM AND HOMOCYSTEINE HOMEOSTASIS. GENETIC POLYMORPHISMS IN THESE PATHWAYS CAN ACT SYNERGISTICALLY WITH NUTRITIONAL DEFICIENCIES TO ACCELERATE METABOLIC PATHOLOGY ASSOCIATED WITH OCCLUSIVE HEART DISEASE, BIRTH DEFECTS AND DEMENTIA. A MAJOR UNANSWERED QUESTION IS WHETHER HOMOCYSTEINE IS CAUSALLY INVOLVED IN DISEASE PATHOGENESIS OR WHETHER HOMOCYSTEINEMIA IS SIMPLY A PASSIVE AND INDIRECT INDICATOR OF A MORE COMPLEX MECHANISM. S-ADENOSYLMETHIONINE AND S-ADENOSYLHOMOCYSTEINE (SAH), AS THE SUBSTRATE AND PRODUCT OF METHYLTRANSFERASE REACTIONS, ARE IMPORTANT METABOLIC INDICATORS OF CELLULAR METHYLATION STATUS. CHRONIC ELEVATION IN HOMOCYSTEINE LEVELS RESULTS IN PARALLEL INCREASES IN INTRACELLULAR SAH AND POTENT PRODUCT INHIBITION OF DNA METHYLTRANSFERASES. SAH-MEDIATED DNA HYPOMETHYLATION AND ASSOCIATED ALTERATIONS IN GENE EXPRESSION AND CHROMATIN STRUCTURE MAY PROVIDE NEW HYPOTHESES FOR PATHOGENESIS OF DISEASES RELATED TO HOMOCYSTEINEMIA.	2002	
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 
16  1661  27 DOWN-REGULATION OF REDUCED FOLATE CARRIER GENE (RFC1) EXPRESSION AFTER EXPOSURE TO METHOTREXATE IN ZR-75-1 BREAST CANCER CELLS. METHOTREXATE (MTX) IS ADMINISTERED IN INTERVALS OF ONE WEEK OR LONGER IN THE TREATMENT OF CANCER AND AUTOIMMUNE DISEASE. EARLY STUDIES SUGGESTED THAT DAILY MTX ADMINISTRATION WAS ASSOCIATED WITH DECREASED EFFECTIVENESS AND INCREASED TOXICITY, LEADING TO SCHEDULES OF ADMINISTRATION THAT INCLUDE PERIODIC INTERVALS OF REST DURING CHRONIC MTX THERAPY. WE HYPOTHESIZED THAT THESE OBSERVATIONS MAY BE THE RESULT OF THE DOWN-REGULATION OF THE REDUCED FOLATE CARRIER, THE MAJOR ROUTE OF CELLULAR UPTAKE OF BOTH MTX AND THE ENDOGENOUS FOLATES, AFTER MTX EXPOSURE. WE EXPOSED FOLATE-DEPLETED ZR-75-1 BREAST CANCER CELLS TO LOW-DOSE MTX IN THE PRESENCE OF HYPOXANTHINE, ADENOSINE AND THYMIDINE. AFTER 72 H, THE INITIAL RATE OF MTX UPTAKE HAD DECREASED TO 22% OF THE DAY 0 VALUE. WESTERN BLOT ANALYSIS SHOWED DOWN-REGULATION OF RFC1 PROTEIN EXPRESSION, AND NORTHERN BLOT ANALYSIS SHOWED A CORRESPONDING DECREASE IN RFC1 RNA LEVELS. USING AN RT-PCR ASSAY, WE FOUND THAT LEVELS OF RNA TRANSCRIPTS CONTAINING EACH OF THE THREE RFC1 5' NONCODING EXONS WERE DECREASED AFTER EXPOSURE TO MTX, SUGGESTING THAT MTX EXPOSURE CAUSES TRANSCRIPTIONAL DOWN-REGULATION OF RFC1. PROMOTER-REPORTER CONSTRUCT ASSAYS DEMONSTRATED DECREASED ACTIVITY OF RFC1 PROMOTER ELEMENTS UPSTREAM OF THESE EXONS AFTER MTX EXPOSURE. PREEXPOSURE OF THE ZR-75-1 CELLS TO 5-AZACYTIDINE, A DNA METHYLATION INHIBITOR, FURTHER DECREASED MTX UPTAKE RATHER THAN REVERSE THE INHIBITION OF RFC1 ACTIVITY, INDICATING THAT RFC1 DOWN-REGULATION AFTER MTX EXPOSURE IS NOT THE RESULT OF METHYLATION OF THE RFC1 PROMOTER. IN SUMMARY, THESE STUDIES DEMONSTRATE THAT MTX EXPOSURE CAN DOWN-REGULATE RFC1 EXPRESSION AND ACTIVITY. THESE ACUTE, INDUCIBLE, EPIGENETIC CHANGES IN RFC1 EXPRESSION MAY ULTIMATELY BE MOLDED INTO THE MORE PERMANENT GENETIC CHANGES THAT RESULT IN THE TRANSPORT-MEDIATED MTX RESISTANCE THAT HAVE BEEN OBSERVED IN MTX-RESISTANT CELL LINES.	2000	
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           
17  1781  30 EFFECT OF 1 YEAR B AND D VITAMIN SUPPLEMENTATION ON LINE-1 REPETITIVE ELEMENT METHYLATION IN OLDER SUBJECTS. BACKGROUND: DISTURBED DNA METHYLATION IS CAUSALLY RELATED TO CHRONIC DISEASES LIKE CANCER AND ATHEROSCLEROSIS. B VITAMINS ARE COFACTORS REQUIRED FOR METHYL GROUP SYNTHESIS AND MAY THEREFORE AFFECT DNA METHYLATION. VITAMIN D HAS EPIGENETIC EFFECTS. WE TESTED IF B AND D VITAMIN SUPPLEMENTATION HAS AN EFFECT ON GENOMIC LONG INTERSPERSED NUCLEAR ELEMENT-1 (LINE-1) METHYLATION AND THE METABOLITES S-ADENOSYLMETHIONINE (SAM) AND S-ADENOSYLHOMOCYSTEINE (SAH). METHODS: FIFTY SUBJECTS (MEDIAN AGE 68.0 YEARS) WERE SUPPLEMENTED WITH A DAILY ORAL DOSE OF B VITAMINS (500 MICROG FOLIC ACID, 500 MICROG VITAMIN B12 AND 50 MG VITAMIN B6), 1200 IU VITAMIN D AND 456 MG CALCIUM. FASTING BLOOD SAMPLES WERE COLLECTED BEFORE AND AFTER 1 YEAR OF SUPPLEMENTATION. LINE-1 METHYLATION WAS DETERMINED IN GENOMIC DNA FROM BLOOD CELLS AS A SURROGATE FOR WHOLE GENOME METHYLATION. IN ADDITION, SAM, SAH AND TOTAL HOMOCYSTEINE (THCY) WERE MEASURED IN PLASMA SAMPLES. RESULTS: PLASMA HOMOCYSTEINE DECREASED SIGNIFICANTLY AFTER SUPPLEMENTATION (12.8 VS. 9.1 MICROMOL/L; P<0.05), WHEREAS SAM, SAH, THE SAM/SAH RATIO AND LINE-1 METHYLATION DID NOT CHANGE SIGNIFICANTLY. LINE-1 METHYLATION WAS NOT SIGNIFICANTLY CORRELATED WITH SAH, HOMOCYSTEINE OR B VITAMINS. CONCLUSIONS: LONG-TERM VITAMIN B SUPPLEMENTATION HAD NO EFFECT ON LINE-1 METHYLATION IN BLOOD CELLS NOR ON PLASMA LEVELS OF SAM AND SAH. VITAMIN B AND D SUPPLEMENTATION SEEMS TO HAVE NO EFFECT ON DNA METHYLATION, ESPECIALLY IN CASES WHERE NO SEVERE DEFICIENCY EXISTS.	2013	
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             
18  3615  28 IN VITRO FOLATE DEFICIENCY INDUCES DEOXYNUCLEOTIDE POOL IMBALANCE, APOPTOSIS, AND MUTAGENESIS IN CHINESE HAMSTER OVARY CELLS. THE GENETIC AND EPIGENETIC EFFECTS OF NUTRITIONAL FOLATE DEFICIENCY WERE STUDIED IN TWO CHINESE HAMSTER OVARY (CHO) CELL LINES. THE CHO-AA8 CELL LINE (HEMIZYGOUS AT THE APRT LOCUS) AND CHO-UV5 (DNA REPAIR-DEFICIENT MUTANT OF AA8) WERE CULTURED IN HAM'S F-12 MEDIUM OR IN CUSTOM-PREPARED HAM'S F-12 MEDIUM LACKING FOLIC ACID, THYMIDINE, AND HYPOXANTHINE. CELLS CULTURED ACUTELY IN THE FOLATE DEFICIENT MEDIUM EXHIBITED INITIAL GROWTH ARREST, FOLLOWED BY MASSIVE CELL DEATH AND DNA FRAGMENTATION INTO NUCLEOSOMAL MULTIMERS CHARACTERISTIC OF APOPTOSIS. ALTHOUGH PROLONGED CULTURE IN THE FOLATE DEFICIENT MEDIUM WAS CYTOSTATIC AND LETHAL TO THE MAJORITY CELLS, MINOR SUBPOPULATIONS IN BOTH CELL LINES FAILED TO INITIATE CELL DEATH, EXHIBITED PHENOTYPIC ABNORMALITIES, AND ADAPTED A SELECTIVE GROWTH ADVANTAGE UNDER MARGINAL FOLATE CONDITIONS. THESE "RESISTANT" CLONES EXHIBITED MAJOR ALTERATIONS IN DEOXYNUCLEOTIDE POOLS ASSOCIATED WITH AN INCREASE IN MUTANT FREQUENCY AT THE APRT LOCUS AS DETECTED BY RESISTANCE TO CYTOTOXICITY IN 8-AZAADENOSINE. THE MUTATION FREQUENCY IN THE DNA REPAIR-DEFICIENT CHO-UV5 CELLS WAS APPROXIMATELY 100-FOLD GREATER THAN THAT IN THE PARENTAL AA8 CLONES, UNDERSCORING THE IMPORTANCE OF DNA REPAIR UNDER CONDITIONS OF FOLATE DEFICIENCY AND NUCLEOTIDE POOL IMBALANCE. THE ENHANCED MUTATION FREQUENCY IN THE DNA REPAIR-COMPETENT FOLATE-DEFICIENT CHO-AA8 CELLS SUGGESTS THAT DNA REPAIR ACTIVITY IS LESS EFFECTIVE UNDER FOLATE-DEFICIENT CONDITIONS. THESE RESULTS ADD TO THE ACCUMULATING CLINICAL AND EXPERIMENTAL EVIDENCE RELATING CHRONIC FOLATE DEFICIENCY TO GENOMIC INSTABILITY AND CARCINOGENESIS.	1994	
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   
19  4925  32 PARENTAL MICRONUTRIENT DEFICIENCY DISTORTS LIVER DNA METHYLATION AND EXPRESSION OF LIPID GENES ASSOCIATED WITH A FATTY-LIVER-LIKE PHENOTYPE IN OFFSPRING. MICRONUTRIENT STATUS OF PARENTS CAN AFFECT LONG TERM HEALTH OF THEIR PROGENY. AROUND 2 BILLION HUMANS ARE AFFECTED BY CHRONIC MICRONUTRIENT DEFICIENCY. IN THIS STUDY WE USE ZEBRAFISH AS A MODEL SYSTEM TO EXAMINE MORPHOLOGICAL, MOLECULAR AND EPIGENETIC CHANGES IN MATURE OFFSPRING OF PARENTS THAT EXPERIENCED A ONE-CARBON (1-C) MICRONUTRIENT DEFICIENCY. ZEBRAFISH WERE FED A DIET SUFFICIENT, OR MARGINALLY DEFICIENT IN 1-C NUTRIENTS (FOLATE, VITAMIN B12, VITAMIN B6, METHIONINE, CHOLINE), AND THEN MATED. OFFSPRING LIVERS UNDERWENT HISTOLOGICAL EXAMINATION, RNA SEQUENCING AND GENOME-WIDE DNA METHYLATION ANALYSIS. PARENTAL 1-C MICRONUTRIENT DEFICIENCY RESULTED IN INCREASED LIPID INCLUSION AND WE IDENTIFIED 686 DIFFERENTIALLY EXPRESSED GENES IN OFFSPRING LIVER, THE MAJORITY OF WHICH WERE DOWNREGULATED. DOWNREGULATED GENES WERE ENRICHED FOR FUNCTIONAL CATEGORIES RELATED TO STEROL, STEROID AND LIPID BIOSYNTHESIS, AS WELL AS MITOCHONDRIAL PROTEIN SYNTHESIS. DIFFERENTIAL DNA METHYLATION WAS FOUND AT 2869 CPG SITES, ENRICHED IN PROMOTER REGIONS AND PERMUTATION ANALYSES CONFIRMED THE ASSOCIATION WITH PARENTAL FEED. OUR DATA INDICATE THAT PARENTAL 1-C NUTRIENT STATUS CAN PERSIST AS LOCUS SPECIFIC DNA METHYLATION MARKS IN DESCENDANTS AND SUGGEST AN EFFECT ON LIPID UTILIZATION AND MITOCHONDRIAL PROTEIN TRANSLATION IN F(1) LIVERS. THIS POINTS TOWARD PARENTAL MICRONUTRIENTS STATUS AS AN IMPORTANT FACTOR FOR OFFSPRING HEALTH AND WELFARE.	2018	
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            
20  5131  35 POSTWEANING DIETARY FOLATE DEFICIENCY PROVIDED THROUGH CHILDHOOD TO PUBERTY PERMANENTLY INCREASES GENOMIC DNA METHYLATION IN ADULT RAT LIVER. FOLATE PLAYS AN IMPORTANT ROLE IN THE PATHOGENESIS OF SEVERAL CHRONIC DISEASES BY ITS POTENTIAL ABILITY TO MODULATE DNA METHYLATION. WE HYPOTHESIZED THAT THE POSTWEANING PERIOD MIGHT BE A HIGHLY SUSCEPTIBLE PERIOD TO DIETARY FOLATE INTERVENTION FOR DNA METHYLATION PATTERNING. WE DETERMINED THE EFFECTS OF TIMING AND DURATION OF DIETARY FOLATE INTERVENTION PROVIDED DURING THE POSTWEANING PERIOD ON GENOMIC DNA METHYLATION IN ADULT RAT LIVER. IN STUDY 1, WEANLING RATS WERE RANDOMIZED TO RECEIVE AN AMINO ACID-DEFINED DIET CONTAINING 0 (DEFICIENT), 2 (CONTROL), OR 8 (SUPPLEMENTED) MG FOLIC ACID/KG UNTIL 8 WK OF AGE, AFTER WHICH ALL THE RATS WERE FED THE CONTROL DIET UNTIL 30 WK OF AGE. IN STUDY 2, WEANLING RATS WERE FED THE CONTROL DIET UNTIL 8 WK OF AGE AND THEN RANDOMIZED TO RECEIVE THE DIET CONTAINING 0, 2, OR 8 MG FOLIC ACID/KG UNTIL 30 WK OF AGE. IN STUDY 3, WEANLING RATS WERE RANDOMIZED TO RECEIVE THESE DIETS UNTIL 30 WK OF AGE. DIETARY FOLATE DEFICIENCY, BUT NOT SUPPLEMENTATION, PROVIDED DURING THE POSTWEANING PERIOD THROUGH CHILDHOOD TO PUBERTY SIGNIFICANTLY INCREASED GENOMIC DNA METHYLATION BY 34-48% (P < 0.04) IN RAT LIVER THAT PERSISTED INTO ADULTHOOD FOLLOWING A RETURN TO THE CONTROL DIET AT PUBERTY. IN CONTRAST, DIETARY FOLATE DEFICIENCY OR SUPPLEMENTATION CONTINUALLY IMPOSED AT WEANING OR AT PUBERTY DID NOT SIGNIFICANTLY AFFECT GENOMIC DNA METHYLATION IN ADULT RAT LIVER. OUR DATA SUGGEST THAT EARLY FOLATE NUTRITION DURING POSTNATAL DEVELOPMENT PLAYS AN IMPORTANT ROLE IN EPIGENETIC PROGRAMMING THAT CAN HAVE A PERMANENT EFFECT IN ADULTHOOD.	2008