Ornithine decarboxylase in colonic mucosa from patients with moderate or severe Crohn's disease and ulcerative colitis.

Polyamines, as well as ornithine decarboxylase (ODC), the enzyme involved in their synthesis, were reported to be closely related to cell proliferation. In Crohn's disease and ulcerative colitis, cell destruction and proliferation increase in the active stage. The aim of the present study was to determine the ODC in both involved and uninvolved areas of the colonic mucosa of active Crohn's disease and ulcerative colitis patients. The patients were divided in two groups, owing to the different level of activity (severe or moderate), by means of clinical endoscopy, laboratory, and histology evaluations. Subjects with suspected disease, but endoscopically unconfirmed, were used as controls. In all ulcerative colitis and Crohn's disease patients the ODC values both in involved and uninvolved mucosa were significantly lower than in controls. In severe Crohn's disease ODC was significantly reduced versus moderate Crohn's disease only in affected tissues. In all ulcerative colitis patients (moderate or severe) the ODC was significantly decreased in involved mucosa compared with uninvolved mucosa. Severe ulcerative colitis showed the significantly lowest ODC. We suggest that the significant decrease of ODC in the bowel mucosa is closely related to the severity of the disease. The highest decrease of ODC in ulcerative colitis patients would be due both to the enhanced cell destruction, and to the feed-back from exogenous increased polyamine production (bowel bacteria, cell desquamation). Therefore ODC would be considered a sensitive index of the inflammatory derangement of the mucosa, especially in acute ulcerative colitis. We conclude that this behaviour may result in an enhanced risk of neoplasia.