Review of Chemical mediators of inflammination

1. CHEMICAL MEDIATORS OF
INFLAMMINATION

2. - Chemical mediators derived from cells or
plasma
- plasma – derived mediators ( e.g.
compliment protein)
- Must be activated usually by proteolytic
cleavage to acquire biologic activity
- cell – derived mediators are usually in
cellular preformed granules (e.g.
histamine) or ;

3. - Synthesized in response to stimuli e.g
prostagladins, cytokines
Examples of important mediators
CELL DERIVED
Preformed ; stored in cellular granules

4. Mediator Source Function
Histamine mast cells Increased permiability (Venule)
basophils Vasodilatation (arteriole)
Serotonin Platetlets (as above)
Lysosomal enzymes Neutrophils
Cytorines many cells many
cell derived – newly synthesized

5. Mediator Source Function
Prostagladins All leukocytes
Platelets vasodialation
plasma derived
complement system
Are split product of corresponding complement component

6. Mediator
C3a, C5a – stimulates release of histamine
Therefore are mediators of increased
vascular
- Permiabiliy
- Also called Anaphylatoxins because of
release of histamine involved in
anaphylaxis reaction

7. - C3b = opsonin enhances phagocytosis
- C5a also activates lipoxygenase
pathway of Arachidonic acid
metabolism
- There leads to release of other
mediators;
- Leukotrienes
- Lipoxins
Kinin system
activation leads to release of
vasoactive

8. - Mediator “Bradykinin”
Bradykin – increased vascular
permeability
- Mediator of pain
CHRONIC INFLAMMATION
- Inflammation of prolonged duration in
which there is;
- Active inflammation
- tissue destruction
-Attempt at repair

9. Chronic inflammation is characterized
by;
- infiltration of Mononuclear cells
which includes; macrophages,
lymphocytes and plasma cells
- Tissue destruction induces by;
- Persistent of offending agent or
- by inflammatory cells

10. Chronic inflammation is characterized by;
- Infiltration of Mononuclear cells which
includes; macrophages, lymphocytes and
plasma cells
- Tissue destruction induced by;

11. - Attempt at repair – healing by
connective tissue replacement of
damaged tissue
this is accomplished by ;
proliferation of new small blood vessels
(agiogenesis and in particular fibrosis
- Macrophages are component of
mononuclear phagocyte system (MPS)
MPS consist of closely related cells of
bone marrow, origin

12. Bone Marrow Blood Tissue
stem cell – monoblast →monocyte macrophages → Activated
macrophage
macrophages in the dominant cells
coordinating chronic inflammation