Mediators of Inflammation

Question 1

Cell-Derived Mediators (8)

Answer 1

Vasactive Amines
Arachadonic Acid Metabolites
Platelet-Activating Factor
Cytokines
ROS
NO
Lysosomal Enzymes
Neuropepetides

Question 2

Plasma Protein-Derived Mediators (2)

Answer 2

Complement

Coagulin and Kinin

Question 3

Vasoactive Amines (2)

Answer 3

Histamine and Serotonin

Question 4

Vasoactive Amines (storage, cell types, actions, inactivators)

Answer 4

Stored in cells ready for release
Histamine:
Created by Mast cells, Basophils, and Platelets
Causes arterial dilation and endothelial contraction
Inactivated by histaminase
Serotonin:
Created in platelet granules
Causes vasoconstriction to aid in clotting

Question 5

Arachidonic Acid Metabolites (creation, cell types, metabolites, degradation)

Answer 5

Derived from membrane phospholipids
Created by leukocytes, mast cells, endothelials, platelets
Formed by 2 pathways: Prostaglandin/Thromboxane, leukotriene/lipoxin
Inactivated by spontaneous decay and enzymes

Question 6

Prostaglandins and Thromboxanes

Answer 6

Production depends on enzymes present:
ex prostacyclin synthase creates PGI2 in endothelials for vasodilation and anti-platelet aggregation.
ex TXA2 requires another enzyme and has opposite effect
Large variety of actions based on compound and receptor
PGs contribute to pain and fever symptoms

Question 7

Leukotrienes

Answer 7

Mediate functions of inflammation

ex LTB4 for neutrophil chemotaxis

Question 8

Lipoxins

Answer 8

Generated as leukocytes enter tissues

Antagonize Leukotrienes

Question 9

Platelet Activating Factor (Production, Actions)

Answer 9

Produced from membrane phospholipids via phospholipase A2

Promotes platelet aggregation, vasodilation, vascular permeability, bronchoconstriction, cell signaling

Question 10

Cytokines (4)

Answer 10

TNF/IL-1
Chemokines
INF-gamma
IL-12

Question 11

TNF/IL-1

Answer 11

Produced mainly in macrophages/masts/endothelials

Cause endothelial activation (leukocyte recruitment) and induce systemic effects of inflammation.

Question 12

Chemokines (2 types)

Answer 12

CXC: chemotactic for neutrophils
CC: chemotactic for variety of cells (ex eotaxin)

Question 13

IFN-gamma

Answer 13

stimulates classical macrophage activation

Question 14

IL-12

Answer 14

Stimulates growth and function of T cells

Question 15

ROS (Production, Cell Type, Function)

Answer 15

Produced by NADPH oxidase pathway, OH can be converted to hypochlorous radical via myeloperoxidase
Released by neutrophils and macrophages
Function to damage microbes but also damage self

Question 16

Nitric Oxide (Production, Functions)

Answer 16

Made from L-arginine in macrophages and endothelials

Kills microbes, causes vasodilation, antagonizes platelet activation, and reduces leukocyte recruitment.

Question 17

Lysosomal Enzymes (Cell types, function, degradation)

Answer 17

In azurophil granules of neutrophils and granules of macrophages.
Kill microbes, digest ingested material, damage host tissue.
Protease inhibitors limit damage to host (alpha-1-antitrypsin)

Question 18

Neuropeptides (Function, examples)

Answer 18

Initiate inflammation, particularly w/ vascular tone and permeability in lung and GI
Include substance P and 11 amino acid peptide

Question 19

Complement (General points)

Answer 19

Opsonize pathogens, increase vascular permeability and leukocyte chemotaxis, activated by proteolysis.
C3 convertase is critical step.

Question 20

Coagulatin/Kinin

Answer 20

Factor XII, clotting factor that activates kinin system which produces bradykinin for increased vascular permeability, vasodilation, and pain