Potential Relevance of Agmatine as a Virulence Factor of Helicobacter pylori

The polyamine agmatine is able to increasegastric acid secretion. Therefore, we investigatedwhether Helicobacter pylori is able to form and releaseagmatine in vitro and in the human stomach in vivo , and if so, whether a relationship exists amongagmatine concentration in gastric juice, H. pyloriinfection, and gastroduodenal lesions. Agmatine wasdetermined by means of HPLC. In the supernatant of H. pylori cultures, agmatine concentrations up to1500 ng/ml (~12 M) were determined, depending on thenumber of the bacteria in the individual cultures.Agmatine concentration in gastric juice from H. pylori-positive patients was higher than inthat from H. pylori-negative patients. Gastrin in bloodwas elevated in H. pylori-positive patients comparedwith H. pylori-negative patients. Agmatine concentration in gastric juice and serum gastrin levelappeared to be related. In conclusion, H. pylori is ableto form and to release agmatine in vitro and in vivo.This may be assumed to be relevant in vivo, since higher amounts of agmatine are present ingastric juice from H. pylori-positive than from H.pylori-negative patients. Accordingly, agmatine producedby H. pylori may be a virulence factor of this bacterium and may be involved in the pathogenesis ofgastroduodenal lesions.