Delayed healing of gastric ulcer is associated with downregulation of connexin 32 in the gastric mucosa

Background/Aims: Most benign gastric ulcers are healed through suppression of gastric acid by a proton pump inhibitor (PPI). Despite prolonged use of a PPI, some gastric ulcers still do not heal. The primary goal of this study is to investigate the relationship between the expression of connexin 32 (Cx32), a major gap junction protein expressed in the gastric mucosa, and the healing response of gastric ulcers. Methods: Patients with endoscopically verified gastric ulcer were treated with a standard dose of PPI for 12 weeks. Histological studies were performed to exclude malignancy. In total, 10 patients having endoscopically verified gastric ulcers with delayed healing at the end of the PPI course were included in this study. The control group consisted of 11 patients with gastric ulcers that healed normally. The expression of Cx32 in the gastric mucosa of the ulcer margin was analyzed by immunoblotting. Results: Patients with gastric ulcer showing delayed healing had significantly reduced Cx32 expression in the gastric mucosa compared with the patients in whom the ulcers healed normally (i.e., controls). Age, sex, presence of duodenal ulcers, location and size of gastric ulcer, ulcer staging, Helicobacter pylori infection, use of nonsteroidal anti-inflammatory drugs (NSAIDs) and aspirin, smoking, and alcohol consumption were similar in both the control and delayed healing groups. H. pylori infection, use of NSAIDs, smoking, and alcohol consumption all had no significant impacts on the expression of Cx32. Age and expression of Cx32 were not correlated. Conclusion: Downregulation of Cx32 in the gastric mucosa of the ulcer margin may predict delayed healing in patients with gastric ulcer following acid-suppression therapy. Copyright (C) 2015, The Gastroenterological Society of Taiwan, The Digestive Endoscopy Society of Taiwan and Taiwan Association for the Study of the Liver. Published by Elsevier Taiwan LLC. All rights reserved.