BIOCHEMISTRY - Mediators of Inflammation Flashcards
What are the five main groups of acute inflammatory mediators?
Vasoactive amines
Arachidonic acid metabolites
Cytokines
Chemokines
Complement proteins
What are inflammatory mediators produced by?
Immune cells
Tissue cells
Liver
What are the two main vasoactive amines involved in the immediate, transient, acute inflammatory response?
Histamine
Serotonine
Which cell type produces histamine?
Mast cells
What are the five possible stimuli for histamine release?
Trauma
Cold
Heat
Binding of IgE antibodies
Anaphylatoxins
Which histamine receptor is present on the surface of microvascular endothelial cells?
H1 receptors are present on the surface of microvascular endothelial cells
What are the three main roles of histamine in acute inflammation?
Dilation of arterioles
Increased vascular permeability
Eosinophil chemotaxis
List an example of a histamine inhibitor
H1 receptor antagonist
Which two cell types produce serotonine?
Platelets
Neuroendocrine cells
What is the main function of serotonine in acute inflammation?
Vasoconstriction
Which group of enzymes release arachidonic acid from cell membrane phospholipids?
Phospholipase enzymes
What are the two enzymatic pathways which metabolise free arachidonic acid?
Cyclooxygenase (COX)
Lipoxygenase
Which complement protein activates the lipoxygenase pathway?
C5a activates the lipoxygenase pathway
Which arachidonic acid metabolites are produced by the cyclooxygenase (COX) pathway?
Prostaglandins
Which arachidonic acid metabolites are produced by the lipoxygenase pathway?
Leukotriens
Lipoxins
(T/F) All arachidonic acid metabolites are pro-inflammatory mediators
FALSE. Prostaglandins and leukotriens are pro-inflammatory mediators however lipoxins are anti-inflammatory mediators
What are the six main roles of prostaglandins and leukotriens in acute inflammation?
Vasodilation
Vasoconstriction
Increased vascular permeability
Chemotaxis
Pain inducement
Fever inducement
What is the main role of lipoxins as an anti-inflammatory mediator?
Inhibition of leukocyte recruitment
What can be used to inhibit the phospholipase enzymes?
Steroids
What can be used to inhibit the cyclooxygenase (COX) pathway?
NSAIDS
Which main cell type produces cytokines?
Macrophages
What are the three possible stimuli for cytokine release?
Microbial products
Antigen-antibody complexes
Foreign bodies
What are the two main roles of cytokines in acute inflammation?
Endothelial cell activation
Leukocyte activation
What is the specific function of the IL-6 cytokine?
IL-6 stimulates local and systemic inflammation
What is the specific function of the IL-17 cytokine?
IL-17 stimulates neutrophil recruitment
What are the functions of TGF-β and IL-1 in chronic inflammation?
TGF-β and IL-1 terminate the immune response and stimulate fibrosis and tissue repair
List two cytokine inhibitors
TNF-antagonists
Steroids
What are the four major groups of chemokines?
C
CC
CXC
CX3C
What are the two main roles of chemokines in acute inflammation?
Leukocyte attachment via integrins
Leukocyte migration
Which cell type is associated with the C group of chemokines?
Lymphocytes
Which four cell types are associated with the CC group of chemokines?
Monocytes
Basophils
Eosinophils
Lymphocytes
Which cell type is associated with the CXC group of chemokines?
Neutrophils
What are the two complement proteins collectively known as anaphylatoxins?
C3a and C5a are collectively known as anaphylatoxins
Which complement protein promotes phagocytosis?
C3b promotes phagocytosis
Which complement proteins promote cell lysis?
MAC complex (C5 - 9)
