What are the Chemical Mediators of Inflammation?

The mediators of inflammation are the substances that initiate and regulate inflammatory reactions. Many mediators have been identified and targeted therapeutically to limit inflammation.

Principal Mediators of Inflammation:

Histamine  Source: (Mast cells, basophils, platelets)  Action: Vasodilation, increased vascular permeability, endothelial activation

Prostaglandins   Source:Mast cells, leukocytes  Action: Vasodilation, pain, fever

Leukotrienes  Source: Mast cells, leukocytes  Action: Increased vascular permeability, chemotaxis, leukocyte adhesion, and activation

Cytokines (TNF, IL-1, IL-6)  Source: Macrophages, endothelial cells, mast cells
 Action: Local: endothelial activation (expression of adhesion molecules). Systemic: fever, metabolic
abnormalities, hypotension (shock)

Chemokines  Source:Leukocytes, activated macrophages   Action: Chemotaxis, leukocyte activation

Platelet-activating factor  Source: Leukocytes, mast cells  Action: Vasodilation, increased vascular permeability, leukocyte adhesion, chemotaxis, degranulation, oxidative burst.

Complement  Source:Plasma (produced in liver)  Action: Leukocyte chemotaxis and activation, direct target killing (membrane attack complex), vasodilation (mast cell stimulation)

Kinins  Source:Plasma (produced in liver)  Action: Increased vascular permeability, smooth muscle contraction, vasodilation, pain