P180 Novel biomarkers associated with inflammatory bowel disease

Abstract

Abstract Background Inflammatory bowel disease (IBD) is a chronic multi-factorial disease characterized by inflammation of the gastrointestinal tract. Currently, the mechanisms underlying the disease are far from being elucidated. Thus, the study of proteins involved in its pathogenesis would allow further insights into the molecular mechanisms underlying IBD. Methods The serum and intestinal mucosa (ileum and left colon) proteomic profiles of patients with Crohn´s disease (CD) and ulcerative colitis (UC) and healthy controls (HC) were analyzed using a label-free quantitative proteomics approach (Table 1). Data mining and pattern recognition techniques were performed to identify hidden relationships that are not detectable using classical linear classifiers, and thus identify potential markers able to discriminate between the different study groups. Six candidate biomarkers were selected for further validation using enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry (IHC) in serum and intestinal tissue samples, respectively (Table 2). Results Comparison of serum proteins between UC patients and HC revealed statistically lower levels of protein 1 and 2 and higher levels of protein 3. The comparison of potential biomarkers between CD and HC group showed lower levels of protein 1 and higher levels of protein 3. In addition, protein 4 was differentially upregulated in CD patients compared to UC (Figure 1A). Regarding the intestinal biopsies, protein 5 showed higher intensity in the IHC staining of ileum from CD patients compared to HC, whereas protein 6 was significantly decreased in left colon and ileum from CD and UC patients compared to HC (Figure 1B). These proteins are involved in thyroxine transport, regulation of chemotactic chemokine activity, inflammatory processes, triglyceride homeostasis, oxidative stress and regulation of NF-kappa-B activation in the cytosol. Conclusion In this study, we have identified a panel of six potential biomarkers that could help to elucidate mechanisms involved in IBD pathogenesis. Their roles in the pathophysiology need to be clarified in further experiments.