Page 54 - Concise Pathology for Exam Preparation ( PDFDrive )

2 Acute and Chronic Inflammation 39

Q. Enumerate the chemical mediators of inflammation.

Ans. Chemical mediators of inflammation may be
1. Cell derived

Sources Mediator Action
Mast cells, basophils Histamine a Vasodilatation, increased permeability, endothelial
and platelets activation, itching and pain
Platelets and entero- Serotonin a Actions like histamine but less potent
chromaffin cells
Neutrophils and Lysosomal Tissue damage
macrophages enzymes a
All leukocytes and Platelet-activating Increased vascular permeability
endothelial cells factor b
b
All leukocytes Leukotrienes LTC4, LTD4 and LTE4
(slow reacting • Increased permeability of vessels
substances of • Smooth muscle contraction
anaphylaxis) • Vasoconstriction
• Bronchoconstriction
LTB4
• Chemotaxis
• Cell adherence
All leukocytes, plate- Prostaglandins b PGD2 and PGE2
lets and endothelial • Vasodilatation
cells • Bronchodilatation
• Increased permeability of vessels
PGF2a
• Vasodilatation
• Bronchoconstriction
TXA2
• Vasoconstriction
• Bronchoconstriction
• Platelet aggregation
PGI2
• Vasodilatation
• Bronchodilatation
• Inhibition of platelet aggregation
Lymphocytes, macro- Cytokines b Increased leukocyte adherence, thrombosis, fibro-
phages and endo- blastic proliferation and acute phase reaction
thelial cells (IL8 chemotactic for neutrophils, PF4 chemo-
tactic for neutrophils, monocytes and eosino-
phils, MCP-1 chemotactic for monocytes and
eotaxin chemotactic for eosinophils)
Macrophages Nitric oxide b Vasodilatation, antiplatelet effect and microbicidal
action
Neutrophils and Oxygen-derived Endothelial damage and increased vascular
macrophages free radicals permeability

a Preformed mediators.
b Newly synthesized mediators.

2. Plasma derived

Sources Mediator Action
Clotting and fibrinolytic system Fibrin split products Increased vascular permeability
Kinin system Kinin/bradykinin Increased vascular permeability
Complement system Anaphylatoxins, C3a, C4a Increased vascular permeability
and C5a

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