Apoptosis and proliferation in Helicobacter pylori-associated gastric intestinal metaplasia

Abstract

Background: Imbalance between apoptosis and proliferation may be one of the mechanisms underlying H. pylori associated gastric carcinogenesis. Aim: To examine the cell kinetics of gastric intestinal metaplasia and the effect of H. pylori eradication. Methods: Endoscopic gastric biopsies were obtained from 100 H. pylori-infected patients. Apoptosis was determined by triphosphate nick-end labelling (TUNEL) and apoptotic nuclei counting, whereas proliferation was assessed by Ki67 immunostaining. Gastric biopsies were repeated in a sub-group of intestinal metaplasia patients after H. pylori eradication. Results: Antral apoptotic index was significantly lower in intestinal metaplasia than in non-intestinal metaplasia (0.19% vs. 0.51%: P < 0.0001) whereas the level of proliferation was comparable (28% vs. 22%, P = 0.15). Serial antral biopsies taken from 14 intestinal metaplasia patients before and 1 year after H. pylori eradication showed a significant drop in proliferation in both intestinal metaplasia (50% vs. 12%, P < 0.001) and non-intestinal metaplasia area (47% vs. 9%, P < 0.001). A similar fall in apoptosis was detected in non-metaplastic region (0.58% vs. 0.38%, P < 0.001) but not in intestinal metaplasia (0.24% vs. 0.27%, P = 0.56), resulting in a significant increase in the apoptosis/proliferation ratio (0.005-0.021; P = 0.03). Conclusions: Dysregulation in apoptosis control of gastric intestinal metaplasia may contribute to gastric carcinogenesis, which may be retarded by clearance of H. pylori.