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The 2005 Nobel Prize Helicobacter pylori. 64 陳冠伃 62 陳治郡 80 楊昀達 91 鄭惟仁 60 陳安婕 75 黃俊諺 71 陳穎鈞 63 陳泊儒 59 郭人碩. 指導助教 : 林博雅. Contents. 得獎者簡介 幽門桿菌介紹 VacA 致病機制 急性慢性胃炎 CagA 致病機轉 Helicobacter 致癌機制 Helicobacter 檢驗與治療 影片總結. About the Laureates --- before they met.
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The 2005 Nobel PrizeHelicobacter pylori 64陳冠伃 62陳治郡 80楊昀達 91鄭惟仁 60陳安婕 75黃俊諺 71陳穎鈞 63陳泊儒 59郭人碩 指導助教:林博雅
Contents • 得獎者簡介 • 幽門桿菌介紹 • VacA致病機制 • 急性慢性胃炎 • CagA致病機轉 • Helicobacter致癌機制 • Helicobacter檢驗與治療 • 影片總結
1951 1981 1979 Barry J. Marshall J. Robin Warren • 1968 1981 1979
1981 Campylobacter-like organisms, CLO • 1982 tissue culture & animal model • 1984 human model • 1989 Helicobacter pylori • 2005 Nobel prize 1981 1984 2005 1982 1989
Helicobacter pylori • about 3 μm in length and 0.5 μm in diameter • Gram-negative and microaerophilic • Use flagella for motility
Stomach acid • Secrete urease for surviving in acid environment. • Spread from person to person through fecal-oral or oral-oral routes. Gastric epithelium
Urease 1.使Hp能在胃部生存 2.尿素檢驗法-胃是否有Hp 1.Adhesion 2.TFSS系統 Flagella Secreted proteins VacA & CagA 1.胃部黏膜細胞的毀損 2.造成胃癌 3.引起一連串的免疫機制
Virulence factor • flagellin(鞭毛蛋白) • urease(尿素酶) • adhesin(黏附素) • vacuolating cytotoxin,VacA(空泡毒素) • cytotoxin associated gene A,CagA(細胞毒素相關蛋白)
Flagellin • The principal flagellum substituent • Switch between multiple flagellin genes • Activity&Toxicity
Adhesin Adhere to stomach cell Releases protease and phospholipase degrades the hydrophobic layer gastric acid erodes stomach
VacA Vacuolating cytotoxin A 30nm 87kD 1980 Timothy Cover H.pylori infects epithelial cells→vacuolation Oligomer Double layer。12-14 Single layer。 6-7
Vacuolation Apoptosis VacA pathways Tight junction
Vacuolation Oligomerization H+ V-ATPase Cl- Channel Apoptosis
Tight junction Inhibit T cell activation
Acute gastritis Chronic gastritis
Acute gastritis Release INF(Interferon)-γ → attract more macrophages to the infected epithelial cells → inflammation INF- γ Microphage Bcell Dendritic cell Activate B cell (little) Release IL-2 → activate TC Positive feedback Release IL-12 (Interleukin 細胞間白素) → activate TH1 cells IL-12
Chronic gastritis Release INF-γ → attract more macrophages to the infected epithelial cells → inflammation INF- γ IL-4 Microphage Dendritic cell Release IL-4 → activate more B cells B cell Release IL-10 → activate TH2 cells → inactivate TH1 cells IL-10 IL-12 Release IL-12 → activate TH1 cells
Comparison IL-10 released by TH2 cells will inactivate TH1 cells → By contrast, TH1 cells in chronic gastritis are less → Reduce the level of inflammation
CagA(cytotoxin associated gene A) an H. pylori virulence factor 1a 120–145-kDa protein exists in 60%~70% H. pylori. CAG PATHOGENICITY ISLAND (PAI) 2cagA-positive and cagA-negative strains. 3 TYPE IV SECRETION SYSTEM(TFSS)
SH2 protein tyrosine phosphatase 2 (SHP-2) SH2:src homology 2 domains PTP:protein tyrosine phosphatase CagApathways
IL-8 assembles monocytes, neutrophils and ROS Leukocytes secrete a. IL-1β ---proinflammatory cytokines b. TNFα ---Tumer necrosis factor
Secrete gastric juice↓ Hp exists Cag A White blood cells release cytokines Gastric epithelial cells More serious inflammation IL-1β TNFα IL-8 Arachidonic acid (花生四烯酸) in the cell membrane turns into prostaglandin (前列腺素) COX-2↑ ROS aggregation White blood cells aggregation + Gastrin ↑ Affect cell physiolgy Activate oncogene Growth factors↑ More white blood cells aggregation Too less gastric juice, too much gastrin → Atrophic gastritis → Abnormal cells proliferation massively Chronic gastritis
VEGF Cag A EGFR Vessels proliferation
After Hp disappears 常見 罕有
Diagnosis & Cure • Ⅰ. Invasive examination 1.Cell cultivation 2.Urease test 3.Tissue examination • Ⅱ. Noninvasive examination 1. Urea breath test 2. Serum examination • Ⅲ. Cure Proton and potassium pump inhibitor amoxicillin, clarithromycin metronidazole.