Quantitative UPLC-MS/MS analysis of the gut microbial co-metabolites phenylacetylglutamine, 4-cresyl sulphate and hippurate in human urine: INTERMAP Study.
The role of the gut microbiome in human health, and non-invasive measurement of gut dysbiosis are of increasing clinical interest. New high-throughput methods are required for the rapid measurement of gut microbial metabolites and to establish reference ranges in human populations. We used ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) -- positive and negative electrospray ionization modes, multiple reaction monitoring transitions -- to simultaneously measure three urinary metabolites (phenylacetylglutamine, 4-cresyl sulphate and hippurate) that are potential biomarkers of gut function, among multi-ethnic US men and women aged 40-59 from the INTERMAP epidemiologic study (n = 2000, two timed 24-hr urine collections/person). Metabolite concentrations were quantified via stable isotope labeled internal standards. The assay was linear in the ranges 1ng/mL (lower limit of quantification) to 1000ng/mL (phenylacetylglutamine and 4-cresyl sulfate) and 3ng/mL to 3000ng/mL (hippurate). These quantitative data provide new urinary reference ranges for population-based human samples: mean (standard deviation) 24-hr urinary excretion for phenylacetylglutamine was: 1283.0 (751.7) μmol/24-hr (men), 1145.9 (635.5) μmol/24-hr (women); for 4-cresyl sulphate, 1002.5 (737.1) μmol/24-hr (men), 1031.8 (687.9) μmol/24-hr (women); for hippurate, 6284.6 (4008.1) μmol/24-hr (men), 4793.0 (3293.3) μmol/24-hr (women). Metabolic profiling by UPLC-MS/MS in a large sample of free-living individuals has provided new data on urinary reference ranges for three urinary microbial co-metabolites, and demonstrates the applicability of this approach to epidemiological investigations.
Section of Biomolecular Medicine, Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, South Kensington Campus, London, SW7 2AZ, UK ; Department of Epidemiology and Biostatistics, School of Public Health, Imperial College London, W2 1PG, UK.
Anisha
A
Wijeyesekera
Philip A
PA
Clarke
Magda
M
Bictash
Ian J
IJ
Brown
Mark
M
Fidock
Thomas
T
Ryckmans
Ivan K S
IK
Yap
Queenie
Q
Chan
Jeremiah
J
Stamler
Paul
P
Elliott
Elaine
E
Holmes
Jeremy K
JK
Nicholson