PTH-113 Effect of ethnicity on the faecal water metabolic profiles in crohn's disease. (June 2019)

• Record Type: Journal Article
• Authors: Powles, Sam TR; Chong, Leo W; Gallagher, Kate I; Hicks, Lucy C; Swann, Jonathan R; Holmes, Elaine; Williams, Horace RT; Orchard, Timothy R
• Is Part Of: Gut. Volume 68(2019)Supplement 2
• Page Start: A90
• Page End: A91
• Publication Date: 2019-06
• Subjects: Gastroenterology -- Periodicals; 616.33
• DOI: 10.1136/gutjnl-2019-BSGAbstracts.172
• Languages: English
• ISSNs: 0017-5749

Abstract

Abstract : Introduction: South Asians (SA) with Crohn's disease (CD) display a different disease phenotype and course (Walker, 2011. AJG.), as well as a different urinary metabolic profile (Marchesi, 2008. J. Proteome Res.). Metabolic profiling of faecal water has distinguished CD from controls previously, but only in Caucasian (Cau) cohorts, characterised by a reduction in short chained fatty acids. In this study, we aimed to compare the metabolic profiles of faecal water in CD patients and healthy controls (H) from Caucasian and South Asian backgrounds. Methods: Samples from 28 CD patients (15 Cau and 13 SA) and 44 healthy controls (20 Cau and 24 SA) were analysed by H 1 NMR spectroscopy. Data was assessed using orthogonal partial least squares discriminant analysis (OPLSDA). Hypothesis-led univariate analysis was also performed using metabolites that have been previously shown to distinguish CD from controls (Marchesi, 2008). These metabolites were as follows: Acetate, Butyrate, Propionate, Lactate, Methylamine, Glutamine, Alanine, Taurine, Valine, and 2-Hydroxybutyrate (2-HIB). Results: Multivariate analysis (table 1 ) demonstrated that the faecal metabolites driving the separation between CD and controls were similar regardless of ethnicity, although statistically significant separation could not be achieved by multivariate analysis in the smallest group (CD v H in Caucasians). Univariate analysis demonstrated a statistically significant reduction in Butyrate, Acetate, 2-HIB, and Methylamine (p < 0.05) in Cau CD patients compared to controls consistent with previous studies, but only a reduction in 2-HIB and Methylamine were seen with statistical significance in SA patients. When directly comparing Cau and SA patients with CD, Butyrate and 2-HIB were significantly different (p = 0.034 and 0.035 respectively) between these ethnic groups. Conclusions: Despite observing consistent changes in the metabolites driving separation between Caucasian and SA patients compared to controls, univariate analysis reveals differences relating to ethnicity, showing that ethnicity influences faecal water metabolic profiles. The effect of ethnicity is likely to be a combination of genetics, diet and environment. Ethnicity therefore must be accounted for as a potential confounder in this type of analysis.