Helicobacter pylori: an invading microorganism? A review
Andreas Munk Petersen1, Karen Angeliki Krogfelt
1Department of Gastrointestinal Infections, Statens Serum Institut, 5 Artillerivej, 2300 Copenhagen S, Denmark.
Abstract:
In this review we evaluate the pros and cons of Helicobacter pylori invasion of epithelial cells as part of the natural history of H. pylori infection. H. pylori is generally considered an extracellular microorganism. However, a growing body of evidence supports the controversial hypothesis that at least a subset of H. pylori microorganisms has an intracellular (intraepithelial) location. Most significant is the fact that H. pylori invades cultured epithelial cells with invasion frequencies similar to Yersinia enterocolitica and better than Shigella flexneri; furthermore, studies of invasion mechanisms suggest that H. pylori invasion of and survival within epithelial cells is not merely a passive event, but requires active participation of the microorganism. Although many studies of human gastric biopsy specimens have failed to demonstrate any intracellular H. pylori, some studies have revealed a minor fraction of H. pylori inside gastric epithelial cells, with possible linkage to peptic ulceration and epithelial cell damage. In conclusion, these data encourage further research to establish whether intracellular H. pylori does play a role in H. pylori colonization of the human stomach and in peptic ulcer pathogenesis.
Insights
Helicobacter pylori may invade epithelial cells, challenging its extracellular view. Research suggests this intracellular location could link to stomach issues and peptic ulcers.
Area of Science:
- Microbiology
- Cell Biology
- Gastroenterology
Background:
- Helicobacter pylori is typically viewed as an extracellular bacterium.
- Emerging evidence suggests a potential intracellular (intraepithelial) location for H. pylori.
- This intracellular hypothesis remains controversial within the scientific community.
Purpose of the Study:
- To review the advantages and disadvantages of Helicobacter pylori invasion into epithelial cells.
- To evaluate the evidence supporting an intracellular role for H. pylori in infection and pathogenesis.
- To discuss the implications of intracellular H. pylori for peptic ulcer disease.
Main Methods:
- Review of existing scientific literature on H. pylori invasion mechanisms.
- Analysis of studies using cultured epithelial cells to assess invasion frequencies.
- Examination of findings from human gastric biopsy specimens.
Main Results:
- H. pylori demonstrates significant invasion capabilities in cultured epithelial cells, comparable to known invasive pathogens.
- Studies indicate H. pylori invasion and survival within cells involve active microbial participation.
- While many biopsies show no intracellular bacteria, some reveal a small fraction within gastric epithelial cells.
Conclusions:
- The intracellular location of H. pylori warrants further investigation.
- Establishing the role of intracellular H. pylori in gastric colonization is crucial.
- Understanding intracellular H. pylori may provide insights into peptic ulcer pathogenesis.
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