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Potential Long-term Consequences of H. pylori Infection
Potential Long-term Consequences of H. pylori Infection
H. pylori infection
Weeks-moths
Chronic superficial gastritis
Years-decades
Chronic superficial gastritis
Lymphoproliferative disease
Chronic atrophic gastritis
Gastric adenocarcinoma
Peptic ulcer disease
MECHANISMS BY WHICH NSAIDs MAY INCUDE MUCOSAL INJURY.
MECHANISMS BY WHICH NSAIDs MAY INCUDE MUCOSAL INJURY.
• Direct toxicity “ion trapping”
Endhothelial effects•Stasis Ischemia
Ephithelial effects ( due to prostaglandin depletion)• HCI secretion• Mucin secretion• HCO3secretion• Surface active
phospholipid secretion• Epithelial cell
proliferation
HEALING (spontaneous or therapeutic)
EROSIONS
ULCER Acid
Risk Factors for NSAIDs Induced Gastroduodenal Ulceration
Risk Factors for NSAIDs Induced Gastroduodenal Ulceration
Established Possible
Advanced age Concomitant infection withHistory of ulcer H. pyloriConcomitant use of glucocorticoids Cigarette smokingHigh-dose NSAIDs Alcohol consumptionMultiple NSAIDsConcomitant use of anticoagulantsSerious or multisystem disease
Disorders Associated with Peptic Ulcer Disease
Disorders Associated with Peptic Ulcer Disease
Strong association Possible association
Syatemic mastocytosis HyperparathyroidismChronic pulmonary disease Coronary artery diseaseChronic renal failure Polycythemia veraCirrhosis Chronic pancreatitisNephrolithiasis Antitrypsin deficiency
SUMMARY OF POTENTIAL MECHANISMS BY WHICH H. PYLORI MAY LEAD TO GASTRIC SECRETORY ABNORMALITIES
SUMMARY OF POTENTIAL MECHANISMS BY WHICH H. PYLORI MAY LEAD TO GASTRIC SECRETORY ABNORMALITIES
Inflammatory cell
Inflammatory cell
ECL
SMS
Corpus
H. pylori
acid
IL-8+
– + – +
+ ++
+
–––+–
–
– –
IL-8+
TNF-IFN-IL-8
TNF-
IL-1
GD
P
D
Bacterial factorsStructureAdhesinsPonnsEnzymes
(urease, vac A, cag A, etc)
Host factorsDurationLocationInflammatory responseGenetics??
Chronic gastritisPeptic ulcer diseaseGastric MALTomaGastric cancer
Reported Pathophysiologic Abnormalities in Patients with Duodenal Ulcers
Reported Pathophysiologic Abnormalities in Patients with Duodenal Ulcers
Abnormality Approximate Frequency, %
Nocturnal acid secretion 70 Duodenal HCO3 secretion 70 Duodenal acid load 65 Daytime acid secretion 50 Pentagastrin-stimulated MAO 40 Gastrin sensitivity 35-40 Basal gastrin 35-40 Gastric emptying 30 pH inhibition of gastrin release 25 postprandial gastrin release 25
NOTE : MAO, maximal acid output
CLASSIFICATION OF GASTRITISCLASSIFICATION OF GASTRITIS
I. Acute gastritis II. Chronic Atrophic GasritisA. Acute H. pylori infection A. Type A : Autoimmune, B. Other acute infectious gastritides body-predominant
1. Bacterial ( other than H. pylori ) B. Type B : H. pylori - related,2. Helicobacter helmanni antral predominant3. Phlegmonous C. Indeterminant4. Mycobacterial5. Syphilitic III. Uncommon Form of Gastritis6. Viral A. Lymphocytic 7. Parasitic B. Eosinophilic8. Fungal C. Crhn’s disease
D. SarcoidosisE. Isolated granulomatous gratritis
RISK FACTORS FOR H. pylori INFECTION
RISK FACTORS FOR H. pylori INFECTION
Birth or residence in developing country
Low socioeconomic status
Domestic crowding
Unsanitary living conditions
Unclean food or water
Exposure to gastric contents of infected individual
REGULATION OF GASTRIC ACID SECRETION AT THE CELLULAR LEVEL
REGULATION OF GASTRIC ACID SECRETION AT THE CELLULAR LEVEL
ANTRUM
FUNDUSParietal cell
CannaliculusHistamine
SomatostatinSomatostatin
Histamine
Somatostatin
Gastrin
Gastrin
Vagus
Acetylcholine
Blood vessel
–– –
–
TubulovesiclesH, K ATPase ECL cell
ECL cell
G cellD cell
D cell
SCHEMATIC REPRESENTATION OF THE STEPS INVOLVED IN SYNTHESIS OF PROSTAGLANDIN E2(PGE2) AND
PROSTACYCLIN (PGI2)
SCHEMATIC REPRESENTATION OF THE STEPS INVOLVED IN SYNTHESIS OF PROSTAGLANDIN E2(PGE2) AND
PROSTACYCLIN (PGI2)
Membrane phospholipids
Phospholipase A2
Arachidonic acid
COX-2inflammation
MacrophagesLeukocytesFibroblastsEndothelium
PGI2, PGE2
InflammationMitogenesisBone formationOther functions?
TXA2, PGI2, PGE2
Gastrointestinal mucosal integrityPlatelet aggregationRenal function
COX-1housekeeping
StomachKidneyPlateletsEndhothelium
COMPONENTS INVOLVED IN PROVIDING GASTRODUODENAL MUCOSAL DEFENSECOMPONENTS INVOLVED IN PROVIDING
GASTRODUODENAL MUCOSAL DEFENSE
EpitheliumHCO3
-
LumenpH 1-2
Mucus gelpH 7HCO3
-
H+ Pepsin
Prostaglandin
Microcirculation
Preepithelial• Mucus• Bicarbonate• Surface active phospholipidsEpithelial• Cellular resistance• Restitution• Growth factors, protaglandins•Cell proliferation
Subepithelial• Blood flow•Leukocyte
GASTRIC PARIETAL CELL UNDERGOING TRANSFORMATION AFTER
SECRETAGOGUE-MEDIATED STIMULATION
GASTRIC PARIETAL CELL UNDERGOING TRANSFORMATION AFTER
SECRETAGOGUE-MEDIATED STIMULATIONStimulatedResting
Canaliculus
H+, K+ -ATPase
KCI
KCI
HCI
cAMP
ACh
Gastrin
HistamineTubulovesicles Active pumps
Ca-
H3O+
ADHESION MOLECULES, CYTOKINE AND CHEMICAL MEDIATOR IN LEUKOCYTE-ENDOTHELIAL INTERACTIONS
ADHESION MOLECULES, CYTOKINE AND CHEMICAL MEDIATOR IN LEUKOCYTE-ENDOTHELIAL INTERACTIONS
Tissue injury
Oxygen radicals, Protease
Activated PMN
Endothelial injury
Endothelial cells
H2O2
PAFC5a
LTB4
IL-8
ThrombinHistamineH2O2
LTC4
LTD4
IL-1TNFLPS
L-selectionSLeX
SLea
IL-8PAF
P-selectin E-selectin ICAM-1 PAF PECAM-1
CollagenaseElastase
CD11/CD18
Rolling Sticking Transmigration
POSSIBLE MECHANISM OF ULCER RECURRENCE
POSSIBLE MECHANISM OF ULCER RECURRENCE
Gastric acid
IL-1, TNF-(NSAID, H. pylori, stress) Neurophil Infiltration
ULCER RECURRENCE
Neutrophil activation
CytokinesChemokines
Monocyte infiltration
Macrophage activation
ULCER SCAR
Cytokines(IL-1, TNF-)Chemokines
(MCP-1, TGF- 1)
Endothelial cell-leukocyte interaction(ICAM-1/LFA-1, ICAM-1/Mac-1)
Gastric Mucosal Oxidative Stress in Response to H. pylori
Gastric Mucosal Oxidative Stress in Response to H. pylori
H. pylori
Urease NH3
NH2CI
H2O2
O2•-
O2
H2O
HO•
Fe2+
OCI-
ROO-
GSH GSSG
CatalaseGSH-Px
Apoptosis
TBA-RS
SOD
CXC-chemokineIL-8, GRO
H. pylori-induced inflammation and inflammatory cytokine IL-8H. pylori-induced inflammation and inflammatory cytokine IL-8
H. pylori
LAP NAP
Epithelial cell
Tissue injury
Oxygen radicals
Adhesion
Neutrophil
Chemotaxis
Transmigration
Venule
Activation
Macrophage
IL-8IL-1TNF
Role of neutrophil-endothelial interactions in the pathogenesis
Role of neutrophil-endothelial interactions in the pathogenesis
Gastric mucosal injury
NSAIDs
LT/PG Monocyte activation
LTC4, LTD4 LTB4
Vasospasm
TNF-
Ischemia-reperfusion
Neutrophil activation(CD11b/CD18)
Endothelial cell activation(ICAM-1)
Neutrophil-endothelial cell interaction
Oxygen radicals Elastase
Oxygen radicals Elastase
Apoptosis
Endothelial cell injury
Extravasated migrationNeutrophil embolism
Hemorrhage Edema
Oxygen radicals Elastase
Ischemia
Gastric Biopsy ProtocolGastric Biopsy ProtocolBIOPSY PROTOCOL
Topographic patterns of chronic, nonspecific gastritis
Topographic patterns of chronic, nonspecific gastritis
The black areas in the schematic of diffuse corporal atrophic gastritis and multifocal atrophic gastritis represent areas of focal atrophy and
intestinal metaplasia
Diffuse Antral Gastritis Diffuse Corporal Atrophic Gastritis
Multifocal Atrophic Gastritis
Reported Abnormalities in Gastric Acid Secretion and Acid Homeostasis in Peptic Ulcer Disease
Reported Abnormalities in Gastric Acid Secretion and Acid Homeostasis in Peptic Ulcer Disease
Duodenal UlcerIncreased
Mass of gastric parietal cellsMaximal acid outputPeak acid output stimulated by meals*Duration of meal-stimulated acid secretionBasal acid outputDaytime acid outputNocturnal acid outputFasting serum gastrin levels*Meal- and GRP-stimulated gastrin levels*Serum concentrations of pepsinogen I*Rate of gastric emptying for liquids
DecreasedBicarbonate production by the proximal duodenum
Gastric UlcerIncreased
Serum levels of pepsinogen IIDuodenogastric reflux
DecreasedMass of gastric parietal cellsMaximal acid output
*Evidence suggests that this abnormality may be a reersible consequence of exobacter pylori infection
GRP, gastrin-releasing peptide
CONDITIONS ASSOCIATED WITH PEPTIC ULCER
CONDITIONS ASSOCIATED WITH PEPTIC ULCER
Duodenal
H. pylori infection
NSAID use
None knownZE, other
Gastric
H. pylori infection
NSAID use
None knownZE, other
Virulence Factors of Helicobacter pylori that Promote Colonization and induce Tissue Injury
Virulence Factors of Helicobacter pylori that Promote Colonization and induce Tissue Injury
Promote Colonization Flagella (for motility) Urease* Adherence factors Induce Tissue Injury Lipopolysaccharide Leukocyte recruitment and activating factors Vacuolating cytotoxin (VacA) Cytotoxin-associated antigen (CagA) Other membrane inflammatory protein (OipA) Heat shock proteins (HspA, HspB)
* Not essential for colonization
Proposed natural history of Helicobacter pylori infection in humans
Proposed natural history of Helicobacter pylori infection in humans
Childhood Old Age
Chronic Active GastritisAcuteGastritisAcuteGastritis
EnvironmentalFactors
EnvironmentalFactors
MultifocalAtrophicGastritis
MultifocalAtrophicGastritis
AntralPredominantGastritis
AntralPredominantGastritis
Gastric CancerGastric Cancer
LymphomaLymphoma
LymphomaLymphoma
Gastric Ulcer
Duodenal Ulcer
Physiologic Functions of Gastric Exocrine Secretions
Physiologic Functions of Gastric Exocrine Secretions
PRODUCT FUNCTION
Hydrochloric acid Provides optimal pH for pepsin and gastric lipase (see below)
Facilitates duodenal inorganic iron absorptionNegative feedback of gastrin releaseStimulation of pancreatic HCO3- secretionSupression of ingested microorganisms
Pepsins Early hydrolysis of dietary proteinsLiberation of vitamin B12 from dietary protein
Gastric lipase Early hydrolysis of dietary triglycerideIntrinsic factor Binding of vitamin B12 for subsequentileal ab-
sorptionMucin/HCO3- Protection against noxious agents
Distribution of human gastric endocrine cells in glands from the oxyntic mucosa
(left) and pyloric mucosa (right)
Distribution of human gastric endocrine cells in glands from the oxyntic mucosa
(left) and pyloric mucosa (right)
Oxyntic Mucosa
ECL, enterochromaffin-like (histamine); EC, enterochromaffin (serotonin); D (somatostatin); G (gastrin)
Pyloric Mucosa
EC 25%
D 26%Other
14%
ECL 35%
EC 29%
D 19%
Other 3%
G 49%
Exocrine Cells within Gastric Glands and Their Secretory Products*,†
Exocrine Cells within Gastric Glands and Their Secretory Products*,†
GLAND EXOCRINEAREA CELLS% OF ANATOMIC WITHIN SECRETORY
TOTAL COUNTERPART GLANDS PRODUCTS
Cardiac Proximal stomach Mucus neck Mucin, PGII(<5%) just below esoph-
agogastric junc- tion
Oxyntic Fundus and body Mucus neck Mucin, PGI and(75%) PGII‡
Chief PGI and PGII, ‡ leptin
Parietal HCI, intrinsic factor§
Pyloric Antrum and pylorus Mucus neck Mucin, PGII
*Pepsinogen I (PGI), includes Pg 1-5; PGII includes Pg6 and Pg7.
†Endocrine cells are also present within glands
‡PGI and PGII are colocalized in zymogen granules and are secreted concurectly
§Some intrinsic factor may also be produced in chief cells and endocrine cells
Factors That May Modulate the Rate of Gastric Emptying
Factors That May Modulate the Rate of Gastric Emptying
Meal FactorsVolume Emptying rate proportional to volumeAcidity Slowing of emptyingOsmolarity Slower emptying of hypertonic mealsNutrient density Emptying rate inversely proportional to
nutrient densityFat Slowing of emptyingCertain amino acids Slowing of emptying (e.g., L-tryptophan)
Other FactorsIleal fat Slowing of emptying (ileal “brake”)Rectal/colonic distention Slowing of emptyingPregnancy Slowing of emptying
GASTRIC GLANDGASTRIC GLAND
MSC
ECL CELL
D CELL
MNC
CC
PC
Anatomic regions of the stomachAnatomic regions of the stomach
Antrum
Pylorus
Pyloric gland mucosa
Body
FundusLower esophageal
sphincter
Oxyntic gland
mucosa