Introduction Metabolomic profiling is a technique which can be used for the discovery of biomarkers which could be used for the non-invasive diagnosis and monitoring of disease by sampling bodily fluids. We investigated urinary metabolomic profiles of patients with active UC, quiescent UC and controls with IBS attending the GI clinic at Glasgow Royal Infirmary.
Methods After obtaining written informed consent, urine samples were collected from 51 patients attending the GI clinic with a confirmed diagnosis of either active UC (12), quiescent UC (26) controls with IBS (14). The samples were analysed by liquid chromatography interfaced with an Orbitrap mass spectrometer. The data generated were modelled by using Simca P 14.
Results Figure 1 shows comparison of profiles from 12 patients with active UC in comparison with 14 controls based on ten metabolites listed in table 1 with their p values and ratios.
Figure 1 Orthogonal partial least squares discriminant analysis model comparing patients with active IBD (AM) and controls (CF). R2X(cum) 0.985, R2Y (cum) 0.889, Q2 (cum) 0.782.
Table 1 Markers used in the model (Figure 1) separating controls and active UC.
Conclusion Separation between active UC and control samples is clear based on ten metabolites. N-methyl histidine has been observed as a marker of increased protein turnover in IBD1 and is elevated in active UC samples in the current dataset along with its metabolite N-methylimidazolone acetate. Glutamine is higher in the IBD samples and is essential for the preservation of gut integrity,2 although how this relates to elevated levels of glutamine in urine is not clear. In addition levels of rhamnose, arabinoate and mannonate which are derived from dietary fibre are altered. Overall there are strong indicators of metabolic changes in the urine of patients with active UC. Some of the putative markers e.g. glutamine are relatively abundant and may be suitable for a simple urinary test. The next stage will be to quantify these markers, validate the findings in a larger cohort and to determine whether they are also present in saliva (also collected from this cohort).
Disclosure of Interest None Declared
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