A population model of folate-mediated one-carbon metabolism.

Published online

Journal Article

BACKGROUND: Previous mathematical models for hepatic and tissue one-carbon metabolism have been combined and extended to include a blood plasma compartment. We use this model to study how the concentrations of metabolites that can be measured in the plasma are related to their respective intracellular concentrations. METHODS: The model consists of a set of ordinary differential equations, one for each metabolite in each compartment, and kinetic equations for metabolism and for transport between compartments. The model was validated by comparison to a variety of experimental data such as the methionine load test and variation in folate intake. We further extended this model by introducing random and systematic variation in enzyme activity. OUTCOMES AND CONCLUSIONS: A database of 10,000 virtual individuals was generated, each with a quantitatively different one-carbon metabolism. Our population has distributions of folate and homocysteine in the plasma and tissues that are similar to those found in the NHANES data. The model reproduces many other sets of clinical data. We show that tissue and plasma folate is highly correlated, but liver and plasma folate much less so. Oxidative stress increases the plasma S-adenosylmethionine/S-adenosylhomocysteine (SAM/SAH) ratio. We show that many relationships among variables are nonlinear and in many cases we provide explanations. Sampling of subpopulations produces dramatically different apparent associations among variables. The model can be used to simulate populations with polymorphisms in genes for folate metabolism and variations in dietary input.

Full Text

Duke Authors

Cited Authors

  • Duncan, TM; Reed, MC; Nijhout, HF

Published Date

  • July 5, 2013

Published In

Volume / Issue

  • 5 / 7

Start / End Page

  • 2457 - 2474

PubMed ID

  • 23857220

Electronic International Standard Serial Number (EISSN)

  • 2072-6643

Digital Object Identifier (DOI)

  • 10.3390/nu5072457

Language

  • eng

Conference Location

  • Switzerland