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1、Peptic Ulcer,Department of Gastroenterology and Hepatology The Second Affiliated Hospital Chongqing Medical University,Introduction,Definition: PU is ulceration which may occur at any site in the gastrointestinal tract that is exposed to acid-pepsin secretion. (“no acid, no ulcer.”) Defects in the g
2、astrointestinal mucosa extending through the muscularis mucosae into the submucosa or muscularis,Histology of stomachwall,epithelium,lamina propria,Definition,Ulcer : defects in the gastrointestinal mucosa penetrate the muscularis mucosa Erosion : small superficial mucosal lesions do not penetrate t
3、he muscularis mucosa ulcer erosion,Introduction,Typical ulcers: Gastric ulcer (GU) , Duodenal ulcer (DU),Epidemiology,Peptic ulcers (PU) occur in up to 1015% of the population at some time, and are more common in men. In DU and GU, men : women=4.46.8:1 and 3.64.7:1 respectively. Duodenal ulcers (DU)
4、 are more common than gastric ulcers (GU). PU occur at different age. DU are about 10 times more common than GU in young patients, but in the older age groups the frequency is about equal.,Introduction,Two major causes: Hp (helicobacter pylori) NSAIDs (non-steroidal anti-inflammatory drugs) Aicd hyp
5、ersecretory states such as Zollinger-Ellison syndrome Main mechanism: Imbalance between aggressive factors and mucosal defenses,aggressive defensive,repairing ,Hp medicine(NSAIDS) gastric acid and pepsin other factors: stress,smoking,coffee, alcohol,mucus(excluding pepsin) bicarbonate(neutralizing a
6、cid) mucosal barrier mucosal blood flow prostaglandins epithelial cell restitution epithelial cell replication,1.Mucus/Bicarbonate Barrier,The first line of defense is mucus and bicarbonate secretion(粘液和碳酸氢盐的分泌). It stabilizes the pH between the lumen and the surface epithelial cells. Mucus gel( 粘液凝
7、胶)in patients with H.p infection was found to be structurally weak.,2.Mucosa Barrier,The second line of defense is the intrinsic epithelial cell defense（上皮细胞防御、粘膜屏障） The mucosal surface is a barrier to acid back diffusion thus maintaining normal intracellular（细胞内） pH.,3.Mucosal Blood Flux,The third
8、line of defense is the rich mucosal blood flow(丰富的粘膜血流屏障). The blood provides a buffer for acid neutralization（中和） as well as adequate nutrition for the metabolic（代谢） demand to maintain mucosal integrity.,4.Others,Prostaglandin(前列腺素), can reduce the secretion of acid. Feedback regulation of gastric
9、secretion.（胃的分泌的反馈调节）,Balance Hypothesis when the balance between aggressive factors and defensive factors was broken , peptic ulcers would occur. gastric ulcer - defensive factors weaken duodenum ulcer - aggressive factors strengthen,H. Pylori and Peptic Ulcer (1) Helicobacter Pylori (HP) - Found i
10、n 1983 by Marshall and Warren. - Lived under micro-oxygen and acidic condition. - Main cause of chronic gastritis and PU. - Secretion of some inflammatory factors: urease, vacuolating cytotoxin, lipopolysaccharide endotoxin, proteinase, lipase and phospholipase A2.,Barry J. Marshall,J. Robin Warren,
11、H.Pylori and Peptic Ulcer,(2)Hp infection breaks the balance between the aggressive factors and defensive/repairing factors. Hp inflammation &immune response damage the mechanism of mucosal defense and repair. Hp gastrin ,acid.,H.Pylori and Peptic Ulcer,(3) Two lines of evidence established HP as a
12、crucial causal factor for development of both DU and GU: (i) the large majority of DU (90%) and GU (75%) are associated with HP. (ii) Several well designed, controlled studies and numerous other less rigorous trials have consistently indicated that successfully curing the HP infection predicts a mar
13、kedly reduced rate of ulcer recurrence.,NSAIDs and Peptic Ulcer (1)Mechanism: Damage gastric mucosal barrier directly. Inhibit the production of endogenous prostaglandin (PG). NSAIDs systemically inhibit gastric COX Reduces mucosal prostaglandin production Limits the ability of the mucosa to defend
14、itself against injury from superimposed factors,NSAIDs and Peptic Ulcer,(2) Risk factors for NSAID ulcers Age: elderly individuals, above 60 Previous history of ulcers or complications Duration of therapy: the first week and the first month of therapy Dose and duration of action and use of multiple
15、NSAIDs Dyspepsia Co-therapy with corticosteroids Others: Hp infection, smoking, etc.,Acid-pepsin and peptic ulcer (1)Peptic ulcers formation are finally dependent upon the acid-peptic activity in gastric juice (2)Peptic activity is closely linked to gastric pH Precursor pepsinogen is converted into
16、active protease at low pH. Pepsin is inactivated when pH is elevated above 4, accounts for the healing of refractory ulcers when the pH is elevated above 4.,Acid-pepsin and peptic ulcer (3)Adequate acid secretion is necessary for DU, GU may occur in low acid concentrations Inhibiting acid secretion promotes healing DU and GU Specially in most GU, maximal gastric acid output (MAO) and basal gastric acid output (BAO) are normal
