2.6 Peptic Ulcer Disease Flashcards
What can H. pylori cause?
gastritis
Peptic ulcer
Gastric cancer
Where is the main site of peptic ulcers?
Duodenum (usually benign)
define: adhesion
coordinates binding of the organism to the host tissue
Define: impedin
Enables the organism to evade one or more of the host defence mechanisms
define: aggressin
causes damage to the host
Define: modulin
increases damage to the host indirectly
What are the two factors that H.pylori require for colonisation?
Urease and flagella
What is the function of urease in h.pylori?
Splits urea into ammonia and CO2 raising the pH in the vicinity
How does h.pylori create ulcers?
The urease splits urea into ammonia creating a falsely high pH which stimulates the antral G cells to secrete gastrin which will act on the parietal cells to release acid - this overwhelms the normal mucosal defence leading to the formation of an ulcer
What is the type 4 secretion system?
used for the communication between bacteria and the exchange of genetic material - DNA uptake and release
What occurs in the type 4 secretion in H.pylori
Injects CagA and peptidoglycan into the host cell which will create an immune response
What are the effects of CagA?
reorganisation of the host cytoskeleton, mediating pedestal formation and cell elongation
Induction of NF-kB and IL-8
Recruitment of epithelial junctional adhesion molecules to the site of bacterial infection
formation of pedestal which will causes apoptosis
What role does Vac A have in h.pylori?
It is an impedin and aggression
It is a pore forming toxin and will induce vacuole formation in cells and disrupt cell signalling
What are the adhesions of h.pylori?
BabA, SabA, ALPAB, HopZ, Urease
What are the impedins of h.pylori
VacA and urease
