Metabolic Analysis in Human Sulfur Amino Acid Deficiency
Summary
Varied food intake, disease, and genetic differences result in complex diet-health interactions. In principle, information-rich metabolic analyses combined with bioinformatic tools provide an approach to explore these interactions. This project is a feasibility study of the use of high-resolution 1H-nuclear magnetic resonance (NMR) to study metabolic perturbations induced by a deficiency in sulfur amino acids (SAA). The investigators will 1) test the hypothesis that deficient dietary intake of SAA in humans results in oxidation of reduced glutathione (GSH)/oxidized glutathione (GSSG) redox and 2) determine whether 1H-NMR of blood and urine detects metabolic changes due to SAA deficiency.
Description
Varied food intake, disease, and genetic differences result in complex diet-health interactions. In principle, information-rich metabolic analyses combined with bioinformatic tools provide an approach to explore these interactions. This project is a feasibility study of the use of high-resolution 1H-NMR to study metabolic perturbations induced by deficiency in sulfur amino acids (SAA). In cell culture, sulfur amino acid (SAA) deficiency results in substantial oxidation of glutathione (GSH) redox state. Because GSH redox affects central homeostatic and cell defense mechanisms, redox changes in vivo due to SAA deficiency could induce complex physiologic effects that are not easily predictable by more traditional metabolic analyses. We will 1) test the hypothesis that deficient dietary intake of SAA in humans results in oxidation of GSH/GSSG redox and 2) determine whether 1H-NMR of blood and urine detects metabolic changes due to SAA deficiency. Studies will be performed on 12 healthy individuals (6 males, 6 females) in the Emory General Clinical Research Center (GCRC) using a crossover design (replete, deficient, replete). Kinetic and balance studies will establish the time course and magnitude of changes in SAA and metabolites in blood and urine in response to SAA intake. Plasma GSH/GSSG and cysteine/cystine redox will be measured to determine whether variation in intake of SAA affects steady-state thiol-disulfide redox state. 1H-NMR spectra of blood and urine samples will be used to determine whether metabolic changes unrelated to the direct SAA metabolites can be detected in association with variation in SAA intake. The results will show whether variation in SAA intake is likely to affect health risks associated with thiol-disulfide redox and oxidative stress. Furthermore, because NMR analysis of biofluids can be performed with a high throughput (e.g., 300 samples/day with a flow cell), results will show whether this approach could be useful for nutritional assessment of complex metabolic effects of SAA intake.
Study Design
Allocation: Non-Randomized, Control: Dose Comparison, Endpoint Classification: Efficacy Study, Intervention Model: Single Group Assignment, Masking: Open Label, Primary Purpose: Diagnostic
Conditions
Oxidative Stress
Intervention
dietary amino acids; cysteine and methionine
Location
Emory University Hospital
Atlanta
Georgia
United States
30322
Status
Completed
Source
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Results (where available)
Links
- Source: http://clinicaltrials.gov/show/NCT00253760
- Information obtained from ClinicalTrials.gov on July 15, 2010
Medical and Biotech [MESH] Definitions
Oxidative Stress
A disturbance in the prooxidant-antioxidant balance in favor of the former, leading to potential damage. Indicators of oxidative stress include damaged DNA bases, protein oxidation products, and lipid peroxidation products (Sies, Oxidative Stress, 1991, pxv-xvi).
Sulfur
An element that is a member of the chalcogen family. It has an atomic symbol S, atomic number 16, and atomic weight 32.066. It is found in the amino acids cysteine and methionine.
Amino Acids, Essential
Amino acids that are not synthesized by the human body in amounts sufficient to carry out physiological functions. They are obtained from dietary foodstuffs.
L-amino Acid Oxidase
An enzyme that catalyzes the oxidative deamination of L-amino acids to KETO ACIDS with the generation of AMMONIA and HYDROGEN PEROXIDE. L-amino acid oxidase is widely distributed in and is thought to contribute to the toxicity of SNAKE VENOMS.
Ring Finger Domains
A zinc-binding domain defined by the sequence Cysteine-X2-Cysteine-X(9-39)-Cysteine-X(l-3)-His-X(2-3)-Cysteine-X2-Cysteine -X(4-48)-Cysteine-X2-Cysteine, where X is any amino acid. The RING finger motif binds two atoms of zinc, with each zinc atom ligated tetrahedrally by either four cysteines or three cysteines and a histidine. The motif also forms into a unitary structure with a central cross-brace region and is found in many proteins that are involved in protein-protein interactions. The acronym RING stands for Really Interesting New Gene.
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PubMed Articles
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