TY - JOUR
T1 - Quantification of stable isotope traces close to natural enrichment in human plasma metabolites using gas chromatography-mass spectrometry
AU - Krämer, Lisa
AU - Jäger, Christian
AU - Trezzi, Jean Pierre
AU - Jacobs, Doris M.
AU - Hiller, Karsten
N1 - Funding Information:
We want to thank Angela Hogan from the Integrated Biobank Luxembourg (IBBL) for supplying the whole blood for plasma generation and Hanny M. Boers from Unilever R&D Vlaardingen for support with the plasma samples of the nutritional intervention study.
Publisher Copyright:
© 2018 by the author. Licensee MDPI, Basel, Switzerland.
PY - 2018/3
Y1 - 2018/3
N2 - Currently, changes in metabolic fluxes following consumption of stable isotope-enriched foods are usually limited to the analysis of postprandial kinetics of glucose. Kinetic information on a larger diversity of metabolites is often lacking, mainly due to the marginal percentage of fully isotopically enriched plant material in the administered food product, and hence, an even weaker 13C enrichment in downstream plasma metabolites. Therefore, we developed an analytical workflow to determine weak 13C enrichments of diverse plasma metabolites with conventional gas chromatography-mass spectrometry (GC-MS). The limit of quantification was increased by optimizing (1) the metabolite extraction from plasma, (2) the GC-MS measurement, and (3) most importantly, the computational data processing. We applied our workflow to study the catabolic dynamics of 13C-enriched wheat bread in three human subjects. For that purpose, we collected time-resolved human plasma samples at 16 timepoints after the consumption of 13C-labeled bread and quantified 13C enrichment of 12 metabolites (glucose, lactate, alanine, glycine, serine, citrate, glutamate, glutamine, valine, isoleucine, tyrosine, and threonine). Based on isotopomer specific analysis, we were able to distinguish catabolic profiles of starch and protein hydrolysis. More generally, our study highlights that conventional GC-MS equipment is sufficient to detect isotope traces below 1% if an appropriate data processing is integrated.
AB - Currently, changes in metabolic fluxes following consumption of stable isotope-enriched foods are usually limited to the analysis of postprandial kinetics of glucose. Kinetic information on a larger diversity of metabolites is often lacking, mainly due to the marginal percentage of fully isotopically enriched plant material in the administered food product, and hence, an even weaker 13C enrichment in downstream plasma metabolites. Therefore, we developed an analytical workflow to determine weak 13C enrichments of diverse plasma metabolites with conventional gas chromatography-mass spectrometry (GC-MS). The limit of quantification was increased by optimizing (1) the metabolite extraction from plasma, (2) the GC-MS measurement, and (3) most importantly, the computational data processing. We applied our workflow to study the catabolic dynamics of 13C-enriched wheat bread in three human subjects. For that purpose, we collected time-resolved human plasma samples at 16 timepoints after the consumption of 13C-labeled bread and quantified 13C enrichment of 12 metabolites (glucose, lactate, alanine, glycine, serine, citrate, glutamate, glutamine, valine, isoleucine, tyrosine, and threonine). Based on isotopomer specific analysis, we were able to distinguish catabolic profiles of starch and protein hydrolysis. More generally, our study highlights that conventional GC-MS equipment is sufficient to detect isotope traces below 1% if an appropriate data processing is integrated.
KW - GC-MS
KW - Mass isotopomer distribution (MID)
KW - Nutrition
KW - Plasma
KW - Stable isotope labeling
UR - http://www.scopus.com/inward/record.url?scp=85042301165&partnerID=8YFLogxK
U2 - 10.3390/metabo8010015
DO - 10.3390/metabo8010015
M3 - Article
AN - SCOPUS:85042301165
SN - 2218-1989
VL - 8
JO - Metabolites
JF - Metabolites
IS - 1
M1 - 15
ER -