Cell Derived Mediators of Inflammation

Question 1

What are types of cell-derived mediators of inflammation?

Answer 1

Vasoactive amines
Arachidonic acid metabolites
Nitric oxide
Platelet activating factor
Cytokines

Question 2

What cells produce histamine?

Answer 2

Basophils and mast cells

Question 3

What is the function of histamine?

Answer 3

Increased vascular permeability and increased vasodilation

Question 4

What is the function of serotonin as an inflammatory mediator?

Answer 4

Platelet activation

Question 5

What are two cell-derived vasoactive amines that mediate inflammation?

Answer 5

Histamine and serotonin

Question 6

What is the most important “superstar” cell-derived mediator of inflammation?

Answer 6

Histamine

Question 7

Where are the highest levels of serotonin located in the body?

Answer 7

Gut

Question 8

Where is arachidonic acid located?

Answer 8

Cell membrane

Question 9

What enzyme releases arachidonic acid from the cell membrane?

Answer 9

Phospholipase

Question 10

What plasma derived mediator of inflammation produced from the complement system assists in arachidonic acid metabolism?

Answer 10

C5a

Question 11

What enzyme converts arachidonic acid into leukotrienes and lipoxins?

Answer 11

Lipoxygenase (LOX)

Question 12

What are examples of leukotrienes?

Answer 12

LTB4
LTC4
LTD4
LTE4

Question 13

What is the function of LTB4?

Answer 13

• chemotactic agent for phagocytic cells
• stimulates phagocytic cell adherence
• increases vascular permeability

Question 14

What is the difference between C5a and LTB4 as chemotactic agents?

Answer 14

C5a is a plasma derived chemotactic agent in the complement system while LTB4 is a cell derived chemotactic agent for phagocytes in the LOX pathway

Question 15

What is the function of LTC4, LTD4, and LTE4?

Answer 15

• Bronchoconstriction (smooth muscle contraction)
• increased vasodilation and vascular permeability

Question 16

What leukotrienes are present in asthmatic and type I hypersensitivity reactions?

Answer 16

LTB4, LTC4, LTD4, and LTE4

Question 17

What drug can inhibit the lipoxygenase enzyme and the conversion of arachidonic acid to leukotrienes?

Answer 17

Singulair (or other anti-asthmatics)

Question 18

What enzyme converts arachidonic acid to prostaglandins and thromboxane?

Answer 18

Cyclooxygenase (COX)

Question 19

What is the function of PGE2 and PGD2?

Answer 19

• Vasodilation
• increased vascular permeability

Question 20

What is the function of PGI2?

Answer 20

Inhibits platelet aggregation
(AKA prostacyclin -> keeps the blood cyclin’)

Question 21

What is PGI2 called?

Answer 21

Prostacyclin

Question 22

What is TXA2?

Answer 22

Thromboxane

Question 23

What is the function of TXA2?

Answer 23

• Vasoconstriction
• increases platelet aggregation

Question 24

What drugs can inhibit the cyclooxygenase (COX) enzyme?

Answer 24

NSAIDS such as Vioxx, Celebrex, naproxen, ibuprofen, indomethacin, and aspirin

Question 25

What does fish oil inhibit in the arachidonic acid cascade?

Answer 25

Blockage of linoleic acid conversion to arachidonic acid and blocks arachidonic acid release from the cell membrane

Question 26

What induces the systemic acute-phase reaction?

Answer 26

Cytokines

Question 27

What are the various roles of cytokines in inflammation?

Answer 27

- Synthesis of endothelium adhesion molecules and nitric oxide - Induce aggregation of neutrophils - induce systemic acute-phase reactions

Question 28

What endothelium adhesion molecules are synthesized as a result of cytokines?

Answer 28

LTB4, thrombin, selectins, integrins

Question 29

What is the systemic acute-phase reaction?

Answer 29

- Feeling of being sick due to cytokines activation by macrophages - Fever, decreased appetite, increased protein synthesis, leukocytosis

Question 30

What can stimulate cytokine secretion by macrophages and T lymphocytes?

Answer 30

Endotoxins, immune complexes from a type III hypersensitivity reaction, and physical injury

Question 31

What white blood cells release cytokines?

Answer 31

Macrophages and T lymphocytes

Question 32

What are examples of cell-derived cytokines that mediate inflammation?

Answer 32

IL-1, IL-2, IL-6, IL-8, TNF

Question 33

What is interleukin 1 (IL-1) and what is its function?

Answer 33

- Cytokine known as an "endogenous pyrogen" that is the primary cause of **fever** - Primes WBC for inflammation by increasing adherence and metabolism

Question 34

What is the function of tumor necrosis factor (TNF)?

Answer 34

Triggers cell death

Question 35

What cytokine does tumor necrosis factor (TNF) often get released with?

Answer 35

Interleukin 1 (IL-1)

Question 36

What is interleukin 2 (IL-2) and what is its function?

Answer 36

Cytokine involved in "self tolerance" that trains cells to know the difference between "self" and "non-self"

Question 37

What is interleukin 6 (IL-6) and what is its function?

Answer 37

Cytokine involved in the secondary fever response; Implicated in schizophrenia

Question 38

What is interleukin 8 (IL-8) and what is its function?

Answer 38

Cytokine that functions as a cell-derived chemotactic agent for neutrophils

Question 39

What cells synthesize nitric oxide?

Answer 39

Endothelial cells and macrophages

Question 40

What is the function of nitric oxide?

Answer 40

Vasodilation and cytotoxic as a peroxynitrite free radical

Question 41

What is the function of interferons?

Answer 41

- leukocyte activation - interfere w/ viral replication

Question 42

What is platelet activating factor (PAF)?

Answer 42

- very potent & versatile mediator - derived from membrane phospholipids - synthesized by all inflammatory cells, endothelial cells, & injured tissue

Question 43

What are the functions of PAF?

Answer 43

- increase permeability - vasodilation - platelet aggregation - increase arachidonic acid metabolism - increase leukocyte adherence