Ultrastructural aspects of duodenal mucosa repair during treatment of peptic disease.

We applied scanning electron microscopy (SEM) to the study of duodenal ulcer healing during treatment with an H2-receptor antagonist (ranitidine). We also evaluated the changes in the duodenal mucosa close to the lesion, which appeared endoscopically and histologically normal. Endoscopic biopsies were taken from 8 patients both on the edge of the ulcer and in the upper duodenum, before and after 1, 2, 3, 4 and 8 weeks of treatment. Endoscopy revealed a decrease of the ulcer crater after the first week and a complete healing after three weeks of therapy. The ulcer edge presented a subtotal mucosal atrophy, cellular exfoliation (dome-shaped cells) and changes in microvilli (bridging, branching, blebs). In the first week of treatment, reepithelization was observed: however, cellular exfoliation and changes in microvilli persisted at least up to the end of the first month of treatment. Short and stumped villi began to reappear after one month. The mucosa farthest from the lesion showed the same alterations but to a lesser extent. The changes tended to decrease after treatment. Two months after the end of treatment the duodenal mucosa was endoscopically and histologically normal, while SEM showed altered microvilli. SEM allowed us to investigate the morphogenesis of mucosal repair and to identify minimal cellular alterations which could represent the morphological basis of the disease and its possible recurrence.