Dataset Information

Production of hyperpolarized (13)CO2 from [1-(13)C]pyruvate in perfused liver does reflect total anaplerosis but is not a reliable biomarker of glucose production.

ABSTRACT: In liver, (13)CO2 can be generated from [1-(13)C] pyruvate via pyruvate dehydrogenase or anaplerotic entry of pyruvate into the TCA cycle followed by decarboxylation at phosphoenolpyruvate carboxykinase (PEPCK), the malic enzyme, isocitrate dehydrogenase, or ?-ketoglutarate dehydrogenase. The purpose of this study was to determine the relative importance of these pathways in production of hyperpolarized (HP) (13)CO2 after administration of hyper-polarized pyruvate in livers supplied with a fatty acid plus substrates for gluconeogenesis. Isolated mouse livers were perfused with a mixture of thermally-polarized (13)C-enriched pyruvate, lactate and octanoate in various combinations prior to exposure to HP pyruvate. Under all perfusion conditions, HP malate, aspartate and fumarate were detected within ~ 3 s showing that HP [1-(13)C]pyruvate is rapidly converted to [1-(13)C]oxaloacetate which can subsequently produce HP (13)CO2 via decarboxylation at PEPCK. Measurements using HP [2-(13)C]pyruvate allowed the exclusion of reactions related to TCA cycle turnover as sources of HP (13)CO2. Direct measures of O2 consumption, ketone production, and glucose production by the intact liver combined with (13)C isotopomer analyses of tissue extracts yielded a comprehensive profile of metabolic flux in perfused liver. Together, these data show that, even though the majority of HP (13)CO2 derived from HP [1-(13)C]pyruvate in livers exposed to fatty acids reflects decarboxylation of [4-(13)C]oxaloacetate (PEPCK) or [4-(13)C]malate (malic enzyme), the intensity of the HP (13)CO2 signal is not proportional to glucose production because the amount of pyruvate returned to the TCA cycle via PEPCK and pyruvate kinase is variable, depending upon available substrates.

SUBMITTER: Moreno KX

PROVIDER: S-EPMC4629494 | biostudies-literature | 2015 Oct

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Production of hyperpolarized 13CO2 from [1-13C]pyruvate in perfused liver does reflect total anaplerosis but is not a reliable biomarker of glucose production.

Moreno Karlos X KX Moore Christopher L CL Burgess Shawn C SC Sherry A Dean AD Malloy Craig R CR Merritt Matthew E ME

Metabolomics : Official journal of the Metabolomic Society 20150109 5

In liver, 13CO2 can be generated from [1-13C] pyruvate via pyruvate dehydrogenase or anaplerotic entry of pyruvate into the TCA cycle followed by decarboxylation at phosphoenolpyruvate carboxykinase (PEPCK), the malic enzyme, isocitrate dehydrogenase, or α-ketoglutarate dehydrogenase. The purpose of this study was to determine the relative importance of these pathways in production of hyperpolarized (HP) 13CO2 after administration of hyper-p ...[more]

PMID: 26543443

Similar Datasets

Project description:The detection and treatment monitoring of inflammatory states remain challenging in part due to the multifactorial mechanisms of immune activation and spectrum of clinical manifestations. Currently, diagnostic strategies tend to be subjective and limited quantitative tools exist to monitor optimal treatment strategies. Pro-inflammatory M1 polarized macrophages exhibit a distinct metabolic glycolytic phenotype compared to the continuum of M2 polarization states. In the present study, the distinct metabolic phenotypes of resting and activated macrophages were successfully characterized and quantified using hyperpolarized carbon-13 (13C) labeled pyruvate and its metabolic products, i.e. lactate, as a biomarker of resting, disease and treated states. Methods: Mouse macrophage J774A.1 cells were used as a model system in an NMR compatible bioreactor to facilitate dynamic hyperpolarized 13C measurements. The glycolytic metabolism of the cells in the quiescent or resting state were compared with macrophages stimulated by lipopolysaccharide, a classical M1 activator using hyperpolarized 13C labeled pyruvate. Additionally, the activated macrophages were also treated with a non-steroidal anti-inflammatory drug to assess the changes in hyperpolarized lactate signal. The hyperpolarized lactate signals were then correlated using biochemical and molecular assays. Results: We first validated our model system of inflammatory cells by the hallmarks of M1 polarization using steady state metabolic profiling with high resolution NMR in conjunction with nitric oxide Greiss assay, enzyme activity, and mRNA expression. Subsequently, we clearly showed that the cutting edge technology of hyperpolarized 13C NMR can be used to detect elevated lactate levels in M1 polarized macrophages in comparison to control and non-steroidal anti-inflammatory drug treated M2 states. Conclusion: Hyperpolarized 13C lactate has the potential to serve as a biomarker to non-invasively detect and quantify pro-inflammatory state of immune regulatory cells and its response to therapy.

Dataset Information

Production of hyperpolarized (13)CO2 from [1-(13)C]pyruvate in perfused liver does reflect total anaplerosis but is not a reliable biomarker of glucose production.

Publications

Production of hyperpolarized <sup>13</sup>CO<sub>2</sub> from [1-<sup>13</sup>C]pyruvate in perfused liver does reflect total anaplerosis but is not a reliable biomarker of glucose production.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets