Mucosal enzyme activity for butyrate oxidation; no defect in patients with ulcerative colitis.

BACKGROUND Butyrate is an important energy source for the colon and its metabolism has been reported to be defective in ulcerative colitis. One mechanism for defective butyrate metabolism in patients with ulcerative colitis could be an enzyme deficiency in the beta-oxidation pathway of butyrate. AIMS This study was undertaken to measure the activity of each enzyme involved in the beta-oxidation pathway of butyrate in colonic epithelium. PATIENTS Patients with ulcerative colitis (n = 33), Crohn's colitis (n = 10), and control subjects with colorectal cancer or diverticular disease (n = 73) were studied. METHODS Analysis was carried out using fluorometric and spectrophotometric techniques on homogenised epithelial biopsy specimens. RESULTS Significantly increased butyryl CoA dehydrogenase activity was found in mucosa from patients with ulcerative colitis (33.2 (28.3, 38.1) mumol/g wet weight/min:mean (95% CI)) compared with activity in mucosa from control patients (24.3 (20.9, 27.7) mumol/g wet weight/min:mean (95% CI)) p < 0.02. No significant increase in activity of the enzymes butyryl-CoA synthetase, crotonase or hydroxybutyryl-CoA dehydrogenase was found in patients with ulcerative colitis. In contrast the mucosal thiolase activity was significantly lower in those patients with quiescent colitis (3.21 (2.61, 3.81) mumol/g wet weight/min:mean (95% CI)) when compared with control mucosa (5.69 (5.09, 6.29) mumol/g wet weight/min:mean (95% CI)) p < 0.001. However, mucosal thiolase activity increases with the age of the donor patient and differences in the age range of the patient groups probably account for this finding. CONCLUSIONS This study shows no substantial deficiency of enzyme activity in the beta-oxidation pathway of butyrate in the mucosa of patients with ulcerative colitis in histological remission.