Integrated serum proteins and fatty acids analysis for putative biomarker discovery in inflammatory bowel disease.

The diagnosis and management of Inflammatory bowel disease (IBD), including Crohn's disease (CD) and ulcerative colitis (UC), is still challenging. There is no definitive gold standard diagnostic test, which is made on patient history and with endoscopic and histological findings. This study analyzed serum proteins and fatty acids using mass spectrometry-based techniques. Quantitation of serum proteins was performed by depleting 14 high-abundance proteins, followed by tryptic digestion and LC-MS analysis, while fatty acids were analyzed using GC-MS. Bioinformatic tools were used to identify several new potential biomarkers for an early and non-invasive diagnosis of IBD, and to differentiate CD from UC. Moreover, the diagnostic power of the MS-identified biomarkers was also corroborated by Western Blot and ELISA assays. Hence, we identified the biological functions and pathways involved in the various subsets of IBD. Coagulation, fibrinolysis and acute phase response processes were found to be strongly involved in the condition. The involvement of several fatty acids, such as anti-inflammatory mediators, was also identified. Finally, proteomic and lipidomic data were integrated by using combinatorial and multivariate analyses to discover new combined biomarkers and to study the molecular pathways involved in IBD.