Background: The aim of this study was to examine the impact of elemental diet on mucosal inflammation in Crohn's disease (CD), mainly by cytokine measurements.
Methods: Twenty-eight consecutive patients with active CD were treated with an elemental diet (Elental) for 4 weeks. The mucosal biopsies were obtained from the terminal ileum and large bowel before and after treatment. As a control group, mucosal biopsies were obtained from 20 patients without inflammation. Mucosal cytokine concentrations were measured by enzyme-linked immunosorbent assay.
Results: After treatment, clinical remission was achieved in 20 patients (71%). Endoscopic healing and improvement rates were 44% and 76% in the terminal ileum and 39% and 78% in the large bowel, respectively. Histologic healing and improvement rates were 19% and 54% in the terminal ileum and 20% and 55% in the large bowel, respectively. Before treatment, the mucosal concentrations of interleukin (IL)-1beta, IL-1 receptor antagonist (IL-1ra), IL-6, IL-8, and tumor necrosis factor-alpha in the ileum and large bowel were significantly higher than in controls. These cytokine concentrations decreased to the levels of control after treatment. IL-1ra/IL-1beta ratio in the ileum and large bowel was significantly lower than in controls before treatment. The ratio increased to the level of controls after treatment. The endoscopic and histologic healing of the mucosal inflammation was associated with a decline of the mucosal cytokines and an increase of the IL-1ra/IL-1beta ratio.
Conclusions: The elemental diet (Elental) reduced mucosal cytokine production and corrected an imbalance between proinflammatory and anti-inflammatory cytokines in CD.