SUPEROXIDE-DISMUTASE ACTIVITY IN DUODENAL-ULCER PATIENTS

Objective: To investigate whether duodenal ulcer (DU) is associated wi th increased free radical generation at the site of ulceration and to attempt, indirectly, to confirm the hypothesis by determining activity of free radical scavengers such as superoxide dismutase (SOD). Study design: Prospective study comparing SOD activity in biopsies taken fro m the ulcer edge, and antrum in DU patients before and after one month of treatment to SOD activity in biopsies from the duodenal bulb and a ntrum in a control population. Setting: Institute of Gastroenterology of a university hospital. Study population: Twenty-five patients with DU. The diagnosis was confirmed by endoscopy. Measurements: SOD activi ty in biopsy specimen, red blood cells (RBC) and serum was measured us ing the cytochrome c method by spectrophotometry and expressed as U SO D/mg protein. Helicobacter pylori was diagnosed by the rapid urease le st (CLO test) from antral biopsies. Results: SOD activity was markedly depleted in the ulcer edge (2.78 +/- 0.9 U SOD/mg protein) as compare d to the same patients after one month of treatment (4.59 +/- 2.2 U SO D/mg protein) (P = 0.05) and to biopsies from the duodenal bulb in con trol population (6.7 +/- 2.4 U. SOD/mg protein) (P = 0.05). SOD activi ty in the antrum of both groups was similar. There was no difference i n SOD activity in RBC and serum of both groups. Conclusion: Products o f free radical reactions are implicated in the pathogenesis of DU dise ase. SOD, which is a key enzyme in gastric mucosal protection, is depl eted significantly in the ulcer edge compared with controls and increa ses after healing. However, it is not clear whether this abnormality i n oxygen free radical metabolism reflects, rather than causes, the con dition which characterizes DU.