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Apoptosis and proliferation in Helicobacter pylori-associated gastric intestinal metaplasia
1Department of Medicine & Therapeutics, Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong. wkleung@cuhk.edu.hk
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.