Cytotoxic isolates of <it>Helicobacter pylori </it>from Peptic Ulcer Diseases decrease K⁺-dependent ATPase Activity in HeLa cells

• Main Authors: Archana Ayyagari, Shanjana Awasthi
• Format: Article
• Language: English
• Published: BMC 2003-11-01
• Series: BMC Gastroenterology
• Subjects: <it>Helicobacter pylori</it>; Cytotoxin and ATPase
• Online Access: http://www.biomedcentral.com/1471-230X/3/31

<p>Abstract</p> <p>Background</p> <p><it>Helicobacter pylori </it>is a Gram negative bacterium that plays a central role in the etiology of chronic gastritis and peptic ulcer diseases. However, not all <it>H. pylori </it>positive cases develop advanced disease. This discriminatory behavior has been attributed to the difference in virulence of the bacteria. Among all virulence factors, cytotoxin released by <it>H. pylori </it>is the most important factor. In this work, we studied variation in <it>H. pylori </it>isolates from Indian dyspeptic patients on the basis of cytotoxin production and associated changes in K⁺-dependent ATPase (one of its targets) enzyme activity in HeLa cells.</p> <p>Methods</p> <p>The patients were retrospectively grouped on the basis of endoscopic and histopathological observation as having gastritis or peptic ulcer. The HeLa cells were incubated with the broth culture filtrates (BCFs) of <it>H. pylori </it>isolates from patients of both groups and observed for the cytopathic effects: morphological changes and viability. In addition, the K⁺-dependent ATPase activity was measured in HeLa cells extracts.</p> <p>Results</p> <p>The cytotoxin production was observed in 3/7 (gastritis) and 4/4 (peptic ulcer) <it>H. pylori </it>isolates. The BCFs of cytotoxin producing <it>H. pylori </it>strains reduced the ATPase activity of HeLa cells to 40% of that measured with non-cytotoxin producing <it>H. pylori </it>strains (1.33 μmole Pi/mg protein and 3.36 μmole Pi/mg protein, respectively, p < 0.05). The decreased activity of ATPase enzyme or the release of cytotoxin also correlated with the increased pathogenicity indices of the patients.</p> <p>Conclusions</p> <p>Our results suggest that the isolation of cytotoxic <it>H. pylori </it>is more common in severe form of acid peptic diseases (peptic ulcer) than in gastritis patients from India. Also the cytotoxin released by <it>H. pylori </it>impairs the ion-transporting ATPase and is a measure of cytotoxicity.</p>