This study was designed to determine whether prostaglandins can stimulate the repair of human duodenal epithelium. Ten healthy volunteers were given 50 ml 40% ethanol through an endoscope onto the duodenal mucosa 1-7 cm from the pyloric sphincter; 3 min later, misoprostol (200 micrograms) or inert vehicle (5 ml) was given locally in the same way. One and 5 h later, endoscopy was repeated to evaluate the damage. The conditions of the mucosa were evaluated by endoscopy and by scanning and transmission electron microscopy in biopsies taken at time 0 and 3 min, 1 and 5 h after ethanol. The study was double-blind with a cross-over balanced design. Three minutes after ethanol administration, the duodenal mucosa showed hyperemia with hemorrhagic lesions. Under the electron microscope, the lesions were caused by vascular engorgement or red blood cell extravasation into the submucosa; the epithelium underlining lesions showed loss of superficial cells and damage to the upper layer of the mucosa. One hour after ethanol, there was a striking difference between the two treatment groups, with a substantial recovery of the duodenal epithelium in the misoprostol-treated volunteers. Although spontaneous recovery was evident in the control group, there was also a significant difference at 5 h. Our results suggest that prostaglandins are able to stimulate the recovery of the duodenal epithelium after acute damage.
Mucosal biopsies from patients with Crohn's disease and with ulcerative colitis were studied by scanning electron microscopy. Important abnormalities of the mucosal surface were found in both diseases. For Crohn's disease, the characteristic abnormality was loss of the regularity of the polygonal units, but with preservation of the mucosal integrity and of the normal mucosal design. For ulcerative colitis, the abnormalities were disorganization of the cells, signs of sloughing, and superficial erosions. Patients with Crohn's disease always had a significantly increased number of muciparous cells, while those with ulcerative colitis had obvious signs of decreased mucus production. The lesions of ulcerative colitis could be seen under the scanning electron microscope in mucosal areas that appeared normal endoscopically. We feel therefore that scanning electron microscopy of biopsy specimens from patients with inflammatory bowel diseases can be of great help in differential diagnosis.
