title: A two-compartment mathematical model of neuroglial metabolism using [1-(11)C] acetate.
abstract: The purpose of this study was to develop a two-compartment metabolic model of brain metabolism to assess oxidative metabolism from [1-(11)C] acetate radiotracer experiments, using an approach previously applied in (13)C magnetic resonance spectroscopy (MRS), and compared with an one-tissue compartment model previously used in brain [1-(11)C] acetate studies. Compared with (13)C MRS studies, (11)C radiotracer measurements provide a single uptake curve representing the sum of all labeled metabolites, without chemical differentiation, but with higher temporal resolution. The reliability of the adjusted metabolic fluxes was analyzed with Monte-Carlo simulations using synthetic (11)C uptake curves, based on a typical arterial input function and previously published values of the neuroglial fluxes V(tca)(g), V(x), V(nt), and V(tca)(n) measured in dynamic (13)C MRS experiments. Assuming V(x)(g)=10 × V(tca)(g) and V(x)(n)=V(tca)(n), it was possible to assess the composite glial tricarboxylic acid (TCA) cycle flux V(gt)(g) (V(gt)(g)=V(x)(g) × V(tca)(g)/(V(x)(g)+V(tca)(g))) and the neurotransmission flux V(nt) from (11)C tissue-activity curves obtained within 30 minutes in the rat cortex with a beta-probe after a bolus infusion of [1-(11)C] acetate (n=9), resulting in V(gt)(g)=0.136±0.042 and V(nt)=0.170±0.103 μmol/g per minute (mean±s.d. of the group), in good agreement with (13)C MRS measurements.
authors: Center for Biomedical Imaging, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland. bernard.lanz@epfl.ch
authors: Bernard
authors: B
authors: Lanz
authors: Kai
authors: K
authors: Uffmann
authors: Matthias
authors: M
authors: T Wyss
authors: Bruno
authors: B
authors: Weber
authors: Alfred
authors: A
authors: Buck
authors: Rolf
authors: R
authors: Gruetter
mesh_terms: D000085:Acetates / Q000378:metabolism*; D000818:Animals; D002250:Carbon Radioisotopes; D003198:Computer Simulation; D004734:Energy Metabolism; D018698:Glutamic Acid / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D008959:Models, Neurological; D009010:Monte Carlo Method; D009457:Neuroglia / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D000085:Acetates; D002250:Carbon Radioisotopes; D018698:Glutamic Acid