Lack of commensal flora in Helicobacter pylori-infected INS-GAS mice reduces gastritis and delays intraepithelial neoplasia.
Gastroenterology 2011;
140:210-20. [PMID:
20950613 PMCID:
PMC3006487 DOI:
10.1053/j.gastro.2010.09.048]
[Citation(s) in RCA: 261] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2010] [Revised: 08/31/2010] [Accepted: 09/17/2010] [Indexed: 02/07/2023]
Abstract
BACKGROUND & AIMS
Transgenic FVB/N insulin-gastrin (INS-GAS) mice have high circulating gastrin levels, and develop spontaneous atrophic gastritis and gastrointestinal intraepithelial neoplasia (GIN) with 80% prevalence 6 months after Helicobacter pylori infection. GIN is associated with gastric atrophy and achlorhydria, predisposing mice to nonhelicobacter microbiota overgrowth. We determined if germfree INS-GAS mice spontaneously develop GIN and if H pylori accelerates GIN in gnotobiotic INS-GAS mice.
METHODS
We compared gastric lesions, levels of messenger RNA, serum inflammatory mediators, antibodies, and gastrin among germfree and H pylori-monoinfected INS-GAS mice. Microbiota composition of specific pathogen-free (SPF) INS-GAS mice was quantified by pyrosequencing.
RESULTS
Germfree INS-GAS mice had mild hypergastrinemia but did not develop significant gastric lesions until 9 months old and did not develop GIN through 13 months. H pylori monoassociation caused progressive gastritis, epithelial defects, oxyntic atrophy, marked foveolar hyperplasia, dysplasia, and robust serum and tissue proinflammatory immune responses (particularly males) between 5 and 11 months postinfection (P<0.05, compared with germfree controls). Only 2 of 26 female, whereas 8 of 18 male, H pylori-infected INS-GAS mice developed low to high-grade GIN by 11 months postinfection. Stomachs of H pylori-infected SPF male mice had significant reductions in Bacteroidetes and significant increases in Firmicutes.
CONCLUSIONS
Gastric lesions take 13 months longer to develop in germfree INS-GAS mice than male SPF INS-GAS mice. H pylori monoassociation accelerated gastritis and GIN but caused less severe gastric lesions and delayed onset of GIN compared with H pylori-infected INS-GAS mice with complex gastric microbiota. Changes in gastric microbiota composition might promote GIN in achlorhydric stomachs of SPF mice.
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