Extracellular Vesicle Biomarker May Enable Noninvasive Monitoring of H. pylori

9% of the global population, affecting approximately 4.4 billion people worldwide. In many regions, including Africa, Eastern Europe, and Southeast Asia, prevalence exceeds 50%. Although many infected individuals remain asymptomatic, H. pylori is responsible for about 90% of non-cardia gastric cancers, 92% of mucosa-associated lymphoid tissue (MALT) lymphomas, and a substantial proportion of peptic ulcer disease.

How the organism sustains chronic gastric inflammation and malignant progression has remained unclear, complicating risk stratification and early detection. This gap is clinically important because stomach cancer has a five-year survival rate of only about 40%, largely because it is often diagnosed at an advanced stage. Researchers now describe an extracellular-vesicle (EV)-mediated route that ferries a DNA-binding effector from H. pylori into gastric epithelial cells.

Scientists at the Hudson Institute of Medical Research (Clayton, Victoria, Australia) focused on tumor necrosis factor-α-inducing protein (Tipα), a virulence factor found in every stomach-infecting H. pylori strain and previously linked to inflammation and cancer development. Although Tipα has been studied for years, earlier findings were conflicting: some studies suggested that it triggers strong inflammation by increasing tumor necrosis factor (TNF), while others indicated that its effects may vary by strain.

The Hudson team found that Tipα is packaged inside H. pylori EVs rather than freely secreted. EVs proved the main release route and delivered Tipα into the nucleus of human gastric cells, where it bound host DNA. In cell models, EV-associated Tipα dampened inflammation by lowering TNF and interleukin-8 (IL-8), suggesting that Tipα behaves differently when delivered through EVs.

Using biochemical analysis, imaging, and cell-based assays, the study provides the first biochemical evidence of an H. pylori virulence factor packaged within EVs. The amount of EV-secreted Tipα varied by strain, although any link to cancer risk remains unresolved. The findings help reconcile earlier contradictions by showing that Tipα activity depends, at least in part, on how the protein is delivered to host cells.

The work, published in the Journal of Extracellular Vesicles, involved UNSW Sydney and collaborators in Thailand, Brazil, the United States, and France. The team noted potential avenues under investigation, including detecting Tipα-containing EVs in blood, saliva, or gastric fluid and approaches that target EV-mediated delivery. Such advances could support earlier identification of patients at risk for severe disease.

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Hudson Institute of Medical Research