APPLICATION OF METABOLOMICS IN HUMAN HEALTH AND DISEASE

Abstract

Metabolomics remains one of the rapidly growing tools for the identification of new disease diagnostic biomarkers. Mass spectrometry (MS) coupled to a liquid chromatographic (LC) system and nuclear magnetic resonance (NMR) are the two major analytical plafroms currently employed in metabolomic profiling studies of complex biofluid samples. However, due to its inherent higher sensitivity and fast data acquisition, MS remains one of the most dominant analytical techniques used in metabolomics. In this project, metabolomics was employed in various studies to assess metabolite biomarkers associated with health and disease. All the studies employed liquid chromatography-mass spectrometry (LC-MS) on an Orbitrap Exactive mass analyser, and using ZIC-pHILIC or/and C18 analytical columns. Data was acquired using XCali-bur software and metabolite identification was ascertained based on accurate mass detection, retention time comparisons with authentic external standards, and da-tabase searching. The acquired data was analysed using both unsupervised (PCA-X) and supervised (OPLS-DA) models in SIMCA in order to determine discriminating metabolite biomarkers responsible for the observed clustering patterns. Investigation of metabolomic effects of an 80 km ultramarathon exercise among healthy volunteers on a treadmill gave clear separation between the pre- and post-80km samples. The study revealed that many of the amino acids were lowered in plasma post-exercise but the clearest impact of endurance exercise observed was on fatty acid metabolism with respect to formation of medium chain unsaturated and partially oxidised fatty acids and conjugates of fatty acids with carnitines, which suggested that exercise may have led to increased peroxisomal metabolism. It is becoming increasingly clear that human health is strongly impacted by the gut microbiome. Evaluation of metabolomics effects of E. coli incubation in vivo with different carbon sources of 1% cooked meat, 1% maize meal and 1% olive kernel oil revealed that there were significant effects on amino acid, lipid, carbohydrate, and nucleotide metabolism. In addition, there were effects on intermediates of peptide and polyketide biosynthesis, as well as on xenobiotic breakdown products and vit-amin cofactors. These findings suggested that the E. coli metabolome is closely as-sociated with the type of fibre that the microorganism is exposed to and this was consistent with a number of other previous studies. The study of metabolomic effects of dietary fibres on urinary metabolites from pa-tients with Crohn’s disease revealed that each of the 7 dietary fibres did not induce any significant differences in Crohn’s disease patients relative to the controls. On the other hand, it was found that metabolites were affected by the time of sample collection post treatment, and the overall effect was that the levels of specific me-tabolites tended to increase post treatment. The most common pathways affected were those of amino acid metabolism, lipid metabolism, nucleotide metabolism,