A Pilot Study Evaluating Novel Urinary Biomarkers for Crohn's Disease

Although collecting faeces and blood samples are considered non-invasive methods of monitoring Crohn's disease (CD), these methods are less preferred by some patients. This study utilized urine as an alternative to evaluate four disease biomarkers in young adults with active CD before and after exclusive enteral nutrition (EEN) therapy.

Urine samples collected at baseline (W0) and after 8 weeks (W8) of EEN therapy were assayed by ELISA for levels of intestinal fatty acid-binding protein (I-FABP), liver fatty acid-binding protein (L-FABP), claudin-3, and calprotectin. Levels of each biomarker were also compared with standard clinical parameters, including disease indexes, nutrient, and inflammatory markers.

Of the paired urine samples from 14 patients, 10 were female and 12 were newly diagnosed with CD. Urinary I-FABP: Cr (standardized to urine Cr) levels were significantly reduced, while urinary L-FABP: Cr levels increased following EEN therapy. Urinary L-FABP: Cr correlated positively with serum insulin-like growth factor 1 (IGF-1) (r = 0.60, p = 0.02). Urinary CLND3: Cr and calprotectin: Cr levels were not significantly different after treatment.

I-FABP is a potential urinary biomarker of disease activity in adults with CD, while urinary L-FABP may be an indirect marker of nutritional status in adults with CD. CLND3 and calprotectin do not appear to have roles as urinary biomarkers in CD. These findings warrant further investigations using a larger sample size.