Gastric acidity protects mice against prion infection?
BACKGROUND
The transmissible degenerative encephalopathies (TDEs) constitute a distinct group of diseases (scrapie in sheep, bovine spongiform encephalopathy (BSE) and Creutzfeldt-Jakob disease (CJD) in humans). The causal agents are not fully characterized, but are known to be resistant to most inactivation procedures. Ruminants appear to be particularly susceptible to TDEs. The concentrations of hydrochloric acid in their digestive tracts are significantly lower than in monogastric species.


METHODS
The aim of the study was to examine the role of gastric acidity in the protection of mice against infection after intragastric administration of different doses of a scrapie agent. Gastric acidity levels in mice were reduced by adding ranitidine to the drinking water and the animals were observed for neurological symptoms and at sacrifice examined microscopically for spongiform lesions in the brain.


RESULTS
The lower doses of infectious material induced disease significantly more often in mice given ranitidine compared with the controls.


CONCLUSIONS
These data indicate that the normal levels of gastric acidity in mice protect them to some extent from infection with low doses of scrapie agent. This finding is potentially relevant to the pathogenesis of the variant form of CJD, which appears to be associated with the consumption of BSE-infected food products.
Martinsen
T C
TC
Norwegian University of Science and Technology, Faculty of Medicine, Dept of Intra-abdominal Diseases, Trondheim.
Taylor
D M
DM
Johnsen
R
R
Waldum
H L
HL
D000126:Achlorhydria; D000818:Animals; D004198:Disease Susceptibility; D005744:Gastric Acid / Q000502:physiology*; D006635:Histamine H2 Antagonists / Q000494:pharmacology; D051379:Mice; D023421:Models, Animal; D018620:PrPSc Proteins / Q000472:pathogenicity*; D011899:Ranitidine / Q000494:pharmacology; D012608:Scrapie / Q000503:physiopathology*; D013270:Stomach / Q000737:chemistry*
D006635:Histamine H2 Antagonists; D018620:PrPSc Proteins; D011899:Ranitidine