LONG-TERM INFECTION OF THE GASTRIC-MUCOSA WITH HELICOBACTER SPECIES DOES INDUCE ATROPHIC GASTRITIS IN AN ANIMAL-MODEL OF HELICOBACTER-PYLORI INFECTION

Gastric atrophy is a precursor lesion in the development of gastric ca ncer. It has been proposed that atrophy is part of a natural progressi on of inflammatory changes that result from long term infection with t he bacterium Helicobacter pylori. The aim of this study was to test th is hypothesis using an animal model of human Helicobacter infection. C onventional mice were infected with either a cat isolate of Helicobact er felis or a human isolate of ''Gastrospirillum hominis''. All infect ed mice showed a slowly progressive chronic gastritis with increasing numbers of infiltrating mononuclear cells and polymorphonuclear leucoc ytes. After a year and a half, the inflammatory reaction was so severe that atrophic changes were seen in both the antral and fundic mucosa. Control animals initially showed no inflammatory changes however as t he animals aged, the gastric mucosa of some animals became infected wi th a bacterium Helicobacter muridarum that normally inhabits the small and large bowel of the rodent. The presence of this bacterium was als o associated with gastritis and atrophic changes. This is the first re port of experimentally induced atrophic changes induced by a gastric b acterium and opens the way for important experiments that will help be tter understand the induction of gastric cancer.