Watanabe H. Intestinal metaplasia -the effect of Acid on the gastric mucosa and gastric carcinogenesis-.
J Toxicol Pathol 2010;
23:115-23. [PMID:
22272022 PMCID:
PMC3234614 DOI:
10.1293/tox.23.115]
[Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2010] [Accepted: 06/02/2010] [Indexed: 12/25/2022] Open
Abstract
This review concerns stem cells and their relation to intestinal metaplasia. When
gastric regions of mice, Mongolian gerbils or several strains of rats were
irradiated with a total dose of 20 Gy of X-rays given in two fractions,
intestinal metaplasia was only induced in rats. In addition, it was greatly
influenced by rat strain and sex. Alkaline phosphatase (ALP) positive
metaplastic foci were increased by administration of ranitidine (H2
receptor antagonist), crude stomach antigens or subtotal resection of the fundus
and decreased by cysteamine (gastric acid secretion stimulator), histamine or
removal of the submandibular glands. Recent studies have shown that
Cdx2 transgenic mice with gastric achlorhydria develop
intestinal metaplasia and that in men and animals, Helicobacterpylori (H. pyrlori) infection can cause intestinal metaplasias
that are reversible on eradication. Our results combined with findings for
H. pylori infection or eradication and transgenic mice
suggest that an elevation in the pH of the gastric juice due to disappearance of
parietal cells is one of the principal factors for development of reversible
intestinal metaplasia. When different organs were transplanted into the stomach
or duodenum, they were found to transdifferentiate into gastric or duodenal
mucosae, respectively. Organ-specific stem cells in normal non-liver tissues
(heart, kidney, brain and skin) also differentiate into hepatocytes when
transplanted into an injured liver. Therefore, stem cells have a multipotential
ability, transdifferentiating into different organs when transplanted into
different environments. Finally, intestinal metaplasia has been found to
possibly increase sensitivity to the induction of tumors by colon carcinogens of
the 1,2-dimethylhydrazine (DMH), azoxymethane (AOM) or
2-amino-1-methyl-6-phenylimidazo[4.5-b]pyridine (PhIP) type. This carcinogenic
process, however, may be relatively minor compared with the main gastric
carcinogenesis process induced by N-methy1-N’-nitro-N-nitrosoguanidine (MMNG) or
N-methylnitrosourea (MNU), which is not affected by the presence of intestinal
metaplasia. The protocol used in these experiments may provide a new approach to
help distinguish between developmental events associated with intestinal
metaplasia and gastric tumors.
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