Mediators of Inflammation Flashcards
What are the main mediators
Cytokines
Who mediates acute inflammation
TNF
IL-1
IL-17
Chemokines
Where does TNF come from
Macrophages, mast cells, T cells
What doe TNF do?
Expression of endothelial adhesion molc, release of other cytokines, systemic effects
Where does IL-1 come from
Macrophages, endothelial, some epithelial
Where do chemokines come from
macrophages, endothelial cells, T-cells, mast cells
Where does IL-17 come from
T-cells
Who mediates chronic inflammation
IL-12
IFN-gamma
IL-17
Where does IL-12 come from
dendritic cells, macrophages
Where does IFN gamma come from
T-cells, NK cells
What are arachidonic acid metabolites derived from
cell membranes, then cleaved by phospholipids
What is the name for the class of enzymes made from AA metabolites
eicosanoids
What are the types of eicosanoids
cyclooxygenase
lipoxygenase
What do cyclooxygenases produce
prostaglandins
What do lipooxygenases produce
leukotrienes and lipoxins
Why are AA metabolites so important
They produce and mediate almost every step of inflammation
How are steroids and AAs related
Steroids act on phospholipases and prevent AA creation
Pyrogens:
substances that induce fever
How are fevers caused
IL-1 + TNF –> upregulate cyclooxygenases –> produce prostaglandins –> released into hypothalamus –> release neurotransmitters that increase body temp
What are elevated acute-phase proteins
Plasma proteins synthesized in the liver
What are the acute phase proteins
C-reactive protein
Fibrinogen
SAA
What are some negative effects of inflammation
Septic shock
Secondary amyloidosis
What causes septic shock
High levels of bacteria lead to large amounts of TNF and IL-1 being released
Eventually leads to DIC
What causes secondary amyloidosis
Prolonged SAA production –> deposits of misfolded SAA
Can lead to tissue dysfunction
What does TNF do
Stimulates the release of other cytokines
Stimulates endothelial adhesion molecules
Upregulates cyclooxygenase
Mediates granulocyte release
Septic shock
SAA production
What do lipoxins do
Inhibit neutrophil adhesion
What do leukotrienes do
Vasoconstriction
Increase vascular permeability
Leukocyte adhesion
