2004 Annual Report 1.What major problem or issue is being resolved and how are you resolving it (summarize project aims and objectives)? How serious is the problem? What does it matter? The Vitamin Metabolism Laboratory investigates the role of folic acid, and vitamins B12 and B6 in health and disease, particularly the chronic, degenerative diseases that are associated with aging. These vitamins serve as coenzymes in one-carbon metabolism, a network of biochemical reactions essential for normal function. In one-carbon metabolism, a carbon unit, usually from serine, either methylates homocysteine to methionine or is used for purine and thymidylate synthesis. Purines and thymidylates are building blocks for nucleic acids. Methionine is a precursor of S-adenosylmethionine (SAM), the universal methyl donor for many biological compounds, including proteins, lipids, and DNA. Hyperhomocysteinemia, a condition of elevated blood levels of homocysteine, arises from disrupted one carbon metabolism. Hyperhomocysteinemia has been recently shown to be associated with increased risk of vascular disease, stroke and thrombosis and perhaps dementia and Alzheimer's disease. Research conducted within this CRIS relates to several components of the National Program 107 Human Nutrition, specifically, components 2: Diet, genetics, lifestyle, and the prevention of obesity and disease, and 7: Bioavailability of nutrients and food components as it pertains to our work on folate and food folate fortification. This CRIS studies the following issues: a) The extent to which elevated homocysteine levels and disease risk can be attributed to inadequate vitamin states. b) The degree to which inadequate intake, polymorphic mutations, or impaired metabolism are determinants of vitamin status. c) The physiological significance of the C677T mutation in the methylenetetrahydrofolate reductase (MTHFR) gene. MTHFR catalyses the synthesis of 5-methyltetrahydrofolate. The C677T mutation occurs in 12 percent of Caucasians in a homozygous form and results in a partially active thermolabile enzyme. d) The impact of the recently mandated folic acid fortification of flour and cereal grain products on folate and homocysteine status in the US population with emphasis on the recently identified 19 bp deletion in the dihydrofolate reductase (DHFR) gene and relationship to unmetabolized folic acid in plasma e) The underlying mechanisms of the causality of these relationships. 2.List the milestones (indicators of progress) from your Project Plan. Year 1: a. Food analysis for folic acid b. Methionine vs homocysteine: B vitamins, total homocysteine (tHcy) & methionine vs carotid intima-media thickness (IMT), brain function and brain atrophy c. Effect of aging on folate deficiency d. Study 1: Methionine vs homocysteine and CVD in ApoE mice e. Study 4: Rat model of folate/B12 deficiency Year 2. a. Food analysis for folic acid b. Assess folic acid intake c. Methionine vs homocysteine: B vitamins, total homocysteine (tHcy) & methionine vs. IMT, brain function and brain atrophy d. Heritability of tHcy and B12 e. Study 2. B-vitamins vs. homocysteine and behavior. f. Study 4. Rat model of folate/B12 deficiency. Year 3. a. Assess folic acid intake b. Folic acid intake vs. unmetabolized folic acid c. B vitamins vs. heart failure, dementia d. Heritability of tHcy and B12 e. Offspring tHcy vs. parents CVD f. Study 2. B-vitamins vs. homocysteine and behavior g. Study 3. Neurological function in crossed ApoE x CBS deficient mouse model. h. Study 4. Rat model of folate/B12 interaction. Effect of excess folate 3.Milestones: A. Milestones that were scheduled to be addressed in FY2004 were: a. Analysis of nearly 250 food products for the presence of folic acid. b. We began to apply these data to food folate tables and estimation of intake in the Framingham Study cohort. c. Progress on the development of a rat model of B12 deficiency to determine effect of folic acid. d. Development of a rat model to study effect on CVD of methionine vs. homocysteine is progressing as scheduled. Tissue samples are being collected for analysis, which will be conducted next year. B. Milestones for the next 3 years: Year 1 (FY2005): 1. Food analysis for folic acid. 2. Determine the extent to which the homocysteine related diseases (IMT, cognitive impairment, etc.) is attributable to low vitamin status. 3. Study the effect of aging on folate deficiency 4. Methionine vs. tHcy and CVD in ApoE mice 5. Study the potential deleterious effect of high folic acid intake in B12 deficiency states in rat model. Year 2 (FY2006): 1. Food analysis for folic acid. Incorporate the data into the food folate table and estimate folate intake based on dietary folate equivalent. 2. Assess the impact of fortification on folate and homocysteine status using the Framingham cohort as the model. 3. Determine the extent to which the homocysteine related diseases (IMT, cognitive impairment, etc.) is attributable to low vitamin status. 4. Determine heritability of plasma B12 and tHcy levels using the Framingham cohorts. (Years 2 and 3) 5. Study the potential deleterious effect of high folic acid intake in B12 deficiency states in rat model. 6. Study 1: Methionine vs. tHcy and CVD in ApoE mice Year 3 (FY2007): 1. Assess folic acid intakes. incorporate the data into the food folate table and estimate folate intake based on dietary folate equivalent. Assess the impact of fortification on folate and homocysteine status using the Framingham cohort as the model. 2. Determine the effect of fortification on presence of unmetabolized folic acid in plasma and potential health consequences. 3. B vitamins vs. heart failure and dementia 4. Determine heritability of plasma B12 and tHcy levels using the Framingham cohorts. (Years 2 and 3) 5. Study effects of high methionine or high homocysteine in combination of vitamin deficiencies on CVD and brain function in animal models. 4.What were the most significant accomplishments this past year? This project was recently established following completion of the Office of Scientific Quality Review process. Please see report for 1950-51520-005-00D. 5.Describe the major accomplishments over the life of the project, including their predicted or actual impact. This project was recently established following completion of the Office of Scientific Quality Review process. Please see report for 1950-51520-005-00D. 6.What science and/or technologies have been transferred and to whom? When is the science and/or technology likely to become available to the end-user (industry, farmer, other scientists)? What are the constraints, if known, to the adoption and durability of the technology products? This project was recently established following completion of the Office of Scientific Quality Review process. Please see report for 1950-51520-005-00D. 7.List your most important publications in the popular press and presentations to organizations and articles written about your work. This project was recently established following completion of the Office of Scientific Quality Review process. Please see report for 1950-51520-005-00D.