Abstract
BACKGROUND: In the Western world, the incidence of oesophageal adenocarcinoma has increased over the last 30 years coinciding with a decrease in the prevalence of Helicobacter pylori. Trends of increasing oesophageal adenocarcinoma can be linked causally to increasing gastro-oesophageal reflux disease (GORD) which can be linked to an increasingly obese population. However, there is no plausible biological mechanism of association between H. pylori, obesity, and GORD. Ghrelin, a peptide produced in the stomach, which regulates appetite, food intake, and body composition, was studied in H. pylori positive asymptomatic subjects. METHODS: Plasma ghrelin, leptin, and gastrin were measured for six hours after an overnight fast, before and after cure of H. pylori in 10 subjects. Twenty four hour intragastric acidity was also assessed. RESULTS: After cure, median (95% confidence intervals) integrated plasma ghrelin increased from 1160.5 (765.5-1451) pg/ml x h to 1910.4 (1675.6-2395.6) pg/ml x h (p=0.002, Wilcoxon's rank sum test), a 75% increase. This was associated with a 14% increase in 24 hour intragastric acidity (p=0.006) and non-significant changes in leptin and gastrin. There was a significant positive correlation between plasma ghrelin and intragastric acidity (r(s) 0.44, p=0.05, Spearman's rank correlation). CONCLUSIONS: After H. pylori cure, plasma ghrelin increased profoundly in asymptomatic subjects. This could lead to increased appetite and weight gain, and contribute to the increasing obesity seen in Western populations where H. pylori prevalence is low. This plausible biological mechanism links H pylori, through increasing obesity and GORD, to the increase in oesophageal adenocarcinoma observed in the West.