Plasma intestinal fatty acid-binding protein fails to predict endoscopic disease activity in inflammatory bowel disease patients

BACKGROUND: Monitoring disease activity in inflammatory bowel disease (IBD) is of major importance to prevent long-term complications. Intestinal fatty acid-binding protein (I-FABP) has been identified as a marker for intestinal damage and correlates with the degree of inflammation. The aim of the present study was to evaluate whether I-FABP can predict active disease or remission in Crohn's disease (CD) and ulcerative colitis (UC) in a real-life IBD cohort. METHODS: In total, 70 patients with endoscopic disease activity available and 194 patients with disease activity on the basis of a stringent combi-score of clinical activity index, C-reactive protein, and fecal calprotectin were included. Plasma I-FABP was compared between patients with active disease and remission. In a small subgroup of CD patients, follow-up samples were analyzed. RESULTS: In CD (139.2 vs. 119.2 pg/ml; P=0.37) and UC (107.8 vs. 151.8 pg/ml; P=0.33), the median I-FABP did not differ in endoscopic active disease versus remission. In UC patients with active disease on the basis of the combi-score, the median I-FABP (106.8 vs. 172.0 pg/ml; P=0.03) was significantly lower than in patients in remission, but not in CD (145.5 vs. 157.5 pg/ml; P=0.29). Neither disease location in CD nor extent of disease in UC influenced I-FABP significantly. I-FABP was not different (P=0.78) in CD patients with a change in disease activity over time. CONCLUSION: Plasma I-FABP did not differ between endoscopic active disease and remission in both CD and UC. I-FABP was lower in active UC but not CD on the basis of the combi-score. On the basis of these findings, I-FABP has no potential as a novel noninvasive biomarker for disease activity in IBD.