Serum metabolic profiling in inflammatory bowel disease.

Background: The inflammatory bowel diseases (IBD), Crohn's disease (CD), and ulcerative colitis (UC), are chronic inflammatory conditions of the gastrointestinal tract whose pathogenesis is not completely understood. (1)H nuclear magnetic resonance (NMR) spectroscopy of serum generates comprehensive metabolic profiles, reflecting systemic metabolism, which may be altered in disease states.

Aim: The aim of this study was to use (1)H NMR-based serum metabolic profiling in the investigation of CD patients, UC patients, and controls, potentially to provide insights into disordered metabolism in IBD, and into underlying mechanisms of disease.

Methods: Serum metabolic profiles were acquired from 67 individuals (24 CD patients, 20 UC patients, and 23 healthy controls). The multivariate pattern-recognition techniques of principal components analysis (PCA) and partial least squares discriminant analysis with orthogonal signal correction (OSC-PLS-DA) were used to investigate differences between cohorts.

Results: OSC-PLS-DA distinguished CD and UC cohorts with significant predictive accuracy, highlighting differences in lipid and choline metabolism. Metabolic profiles of both CD and UC cohorts, and the combined IBD cohort, differed significantly from controls: metabolites of importance in the OSC-PLS-DA models included lipoproteins (especially HDL cholesterol), choline, N-acetylglycoprotein, and amino acids.

Conclusions: (1)H NMR-based metabolic profiling has identified distinct differences in serum metabolic phenotype between CD and UC patients, as well as between IBD patients and controls.