Other Inflammations And Mediators Flashcards
Examples of primary or preformed cell derived mediators of inflammation
Histamine
Serotonin
Lysosomal enzymes
Examples of newly synthesised cell derived mediators of inflammation
PAF NO Prostaglandin Leukotrienes Cytokine Chemokines Free radicals
Plasma derived mediators of inflammation are
Complement
Coagulation
Kinin
Stain for mast cell
Toluidine blue
Histamine
Richest source: mast cell Earliest to be released Causes: 1. Vasodilation 2. Vasoconstriction (larger vessels) 3. Increased vascular permeability
Triggers of histamine
C3a,C5a
IL-1, IL-8
Physical agents like heat, trauma,…
Serotonin
Sources: platelets (major), enterochromaffin cells of GIT
Functions: same as histamine
Lysosomal enzymes that take part in inflammation are located in
Granules of neutrophils Of two types: 1. Primary/azurophillic Large, coarse 2. Secondary Small , fine
Primary granules of neutrophils contain
MPO (myeloperoxidase) BPI (Bacterial Permeability Increasing protein) Lysozyme Neutral proteases Neutrophil elastase Defensins Phospholipase A2
Secondary granules of neutrophils contain
Lysozyme Lactoferrin Type 4 collagenase Phospholipase A2 Gelatinase Alkaline phosphatase
ANCA
Anti Neutrophilic Cytoplasmic Antibody
Two types: 1. C ANCA Anti proteinase 3 2. P ANCA Anti MPO ANCA
PAF
Sources, functions
All leukocytes, mast cells and platelets Most potent inflammatory mediator Function: 1. Increased platelet aggregation 2. Vasodilation 3. Increased permeability 4. Bronchospasm
The major arachidonic acid producing step
Clinical significance
Phospholipids of the cell membrane are acted by phospholipase to produce arachidonic acid
Steroids generally inhibit this step as a result steps are generally anti inflammatory (broad spectrum anti inflammatory)
Products produced by the cyclooxygenase pathway of arachidonic acid
- PGI2 prostacyclin
- TXA2 thromboxane A2
- PGD2, PGE2, PGP-2alpha : prostaglandins
Products of lipoxygenase pathway of arachidonic acid
- Leukotrienes
2. Lipoxins
Cycloxygenase pathway
Arachidonic acid ➡️ PGG2➡️ PGH2➡️: 1. PGI2 2. PGD2, PGE2, PGF2 alpha 3. TXA2 There are two cycloxygenase enzymes: COX-1 and COX-2 (inducible)
PGI2 and TXA2
Prostacyclin
Vasodilation
Decrease platelet aggregation
Role in inflammation
Thromboxane A2
Vasoconstriction
Increases platelet aggregation
Role in hemostasis
General functions of PHD2, PHE2 and PGF2 alpha
Causes vasodilation
Bronchospasm
Increased vascular permeability
Specific functions of prostaglandins
PGE2 - causes fever and pain
PGD2 and PGF2 alpha - role in neutrophil chemotaxis and
PGF2 alpha - uterine and bronchial smooth muscle contraction
Lipoxygenase pathway of arachidonic acid
Arachidonic acid ➡️ 5-HPETE➡️ LTA4 ➡️:
- LTB4 (chemotactic)
- LTC4 ➡️ LTD4➡️ LTE4 (these cause increased vascular permeability and bronchospasm)
Lipoxin functions
Anti inflammatory:
- Inhibits neutrophil chemotaxis
- Inhibits NK cell activity
Leukotrienes antagonists
Montelukast, zafurlukast
Bronchodilators
Treatment of bronchial asthma
Aspirin and other NSAIDs
Inhibits COX-1 and COX-2
Inhibits cycloxygenase pathway
Different types of chemokines
- C-X-C chemokines: neutrophil
- C-C chemokines: all except neutrophils
- C chemokines: lymphocytes
- CX3C chemokines: monocytes
a,b,g,d
C-X-C chemokines
Alpha chemokine
Chemokine specific for neutrophil
Example: IL-8
C-C chemokines
Beta chemokine
Specific for all leucocytes except neutrophils
Eg.,
1. eotaxin -eosinophils
2. MCP-1 : monocytes
3. MIP-1 alpha: both monocytes and macrophages
C chemokine
Gamma chemokine
Specific for lymphocytes
Example: lymphotaxin
CX3C chemokine
Delta chemokine
Specific for monocytes
One example: fractalkine
Important application of chemokine receptor
Chemokine receptors like CXCR4 and CCT5 act as co-receptors for HIV
Characteristics of chronic inflammation
- Infiltration of tissues by mononuclear cells
- Tissue destruction
- Attempts at healing by angiogenesis and fibrosis