Background & aims: Impaired short-chain fatty acid metabolism by the colonocyte has been suggested as a pathogenic factor in ulcerative colitis (UC). The aim of this study was to measure in vivo butyrate metabolism in UC and to correlate butyrate oxidation with colonic permeability.
Methods: Butyrate oxidation was measured by means of a 14CO2-breath test after rectal instillation of 14C-butyrate. 51Cr-ethylenediaminetetraacetic acid (EDTA) was added to the enema, and the urinary % dose excretion of 51Cr-EDTA after 6 hours was a measure for permeability.
Results: Patients with active extensive UC showed a significantly lower butyrate oxidation and increased colonic permeability in comparison to healthy controls. Butyrate oxidation correlated significantly negative with clinical activity. Oxidation of butyrate was not decreased in most patients with inactive extensive UC. In 3 patients with inactive disease and decreased oxidation, a relapse occurred within a few weeks after the test, whereas all patients with normal oxidation maintained their remission for at least 3 months. A significantly negative correlation existed between butyrate oxidation and colonic permeability.
Conclusions: Patients with active extensive UC have a decreased colonic butyrate oxidation. However, the fact that remission is associated with normal oxidation suggests that UC mucosa is not intrinsically altered in butyrate oxidation, making this unlikely to be a primary defect in UC.