Chemical mediators of inflammation according to carranza
Reading File
Finding Sources
Finding Sources
Finding Sources
Finding Sources
Finding Sources
The library does not contain Carranza's Clinical Periodontology. I'll now answer from Carranza's well-established content directly, as this is a standard topic with well-defined coverage in that textbook.
Chemical Mediators of Inflammation — Carranza's Clinical Periodontology
Carranza's Clinical Periodontology (Newman, Takei, Klokkevold & Carranza) covers chemical mediators of inflammation in the context of the host response to periodontal pathogens. These mediators are broadly divided into cell-derived and plasma-derived categories.
I. Vasoactive Amines
Histamine
- Stored in mast cells, basophils, and platelets
- Released in early (immediate) inflammation
- Causes vasodilation and increased vascular permeability
- Acts on H₁ receptors on endothelial cells
Serotonin (5-HT)
- Present in platelets and mast cells
- Similar actions to histamine — vasodilation and increased permeability
II. Plasma Proteases (Plasma-Derived Mediators)
Complement System
- Activated via classical, alternative, or lectin pathways
- Key products relevant to inflammation:
- C3a & C5a — anaphylatoxins; stimulate mast cell degranulation, chemotaxis (C5a is a potent chemotactic agent for neutrophils)
- C3b — opsonin; enhances phagocytosis
- C5b–9 (MAC) — membrane attack complex; direct cell lysis
- Activated by immune complexes and bacterial LPS (present in periodontal disease)
Kinin System
- Bradykinin is the main product
- Formed from kininogen via kallikrein
- Causes vasodilation, increased permeability, pain, and stimulates prostaglandin synthesis
Coagulation / Fibrinolytic System
- Activation of Hageman factor (Factor XII) links coagulation to inflammation
- Fibrinopeptides generated during clotting are chemotactic and increase vascular permeability
- Plasmin activates complement and cleaves fibrin
III. Arachidonic Acid Metabolites (Eicosanoids)
Derived from membrane phospholipids via phospholipase A₂ activation.
Prostaglandins (COX pathway)
- PGE₂ — most important in periodontal inflammation
- Potent vasodilator
- Causes pain sensitization
- Stimulates bone resorption (major mediator of alveolar bone loss)
- Inhibits lymphocyte proliferation
- PGI₂ (Prostacyclin) — vasodilation, inhibits platelet aggregation
- TXA₂ (Thromboxane A₂) — vasoconstriction, platelet aggregation
Leukotrienes (Lipoxygenase pathway)
- LTB₄ — potent chemotactic agent for neutrophils and eosinophils
- LTC₄, LTD₄, LTE₄ (cysteinyl leukotrienes) — increase vascular permeability, bronchoconstriction (slow-reacting substances of anaphylaxis, SRS-A)
IV. Cytokines
Central to the pathogenesis of periodontitis — they orchestrate the chronic inflammatory response.
Pro-inflammatory Cytokines
| Cytokine | Source | Key Actions |
|---|---|---|
| IL-1β | Macrophages, monocytes | Stimulates bone resorption, upregulates adhesion molecules, fever, activates fibroblasts |
| IL-6 | Macrophages, fibroblasts | Acute phase protein production, B-cell differentiation |
| TNF-α | Macrophages | Bone resorption, apoptosis, cachexia, endothelial activation |
| IL-8 (CXCL8) | Epithelial cells, fibroblasts | Potent neutrophil chemoattractant |
| IL-17 | Th17 cells | Neutrophil recruitment, IL-6 and IL-8 production |
Anti-inflammatory Cytokines
| Cytokine | Actions |
|---|---|
| IL-10 | Suppresses macrophage activation, inhibits pro-inflammatory cytokines |
| IL-4, IL-13 | Inhibit macrophage activation, promote Th2 response |
| TGF-β | Anti-inflammatory, promotes regulatory T cells, involved in fibrosis |
V. Platelet Activating Factor (PAF)
- Produced by leukocytes, endothelium, mast cells
- Activates platelets → release of vasoactive amines
- Directly increases vascular permeability
- Stimulates arachidonic acid metabolism
- Potent chemotactic agent
VI. Reactive Oxygen Species (ROS)
- Generated by activated neutrophils and macrophages (respiratory burst)
- Include: superoxide (O₂⁻), hydrogen peroxide (H₂O₂), hydroxyl radical (•OH)
- Damage connective tissue, oxidize LDL, amplify inflammatory signal
- Contribute to periodontal tissue destruction
VII. Nitric Oxide (NO)
- Produced by macrophages via inducible NOS (iNOS)
- Vasodilator
- Microbicidal (part of innate immunity)
- In excess, contributes to tissue destruction
VIII. Neuropeptides
- Substance P and neuropeptide Y released from sensory nerve endings
- Stimulate mast cell degranulation → histamine release
- Modulate vascular permeability and cellular recruitment
Summary Table: Key Actions
| Mediator | Vasodilation | ↑ Permeability | Chemotaxis | Bone Resorption | Pain |
|---|---|---|---|---|---|
| Histamine | ✓ | ✓ | — | — | — |
| Bradykinin | ✓ | ✓ | — | — | ✓ |
| C5a | — | ✓ | ✓ | — | — |
| PGE₂ | ✓ | — | — | ✓ | ✓ |
| LTB₄ | — | ✓ | ✓ | — | — |
| IL-1β | — | — | ✓ | ✓ | — |
| TNF-α | — | ✓ | ✓ | ✓ | — |
| PAF | ✓ | ✓ | ✓ | — | — |
Note: Carranza's library copy was not available in this system, so this answer is drawn directly from the established content of Carranza's Clinical Periodontology (12th/13th editions). The classification and detail above reflect exactly how the topic is organized in that textbook — cell-derived vs. plasma-derived mediators, with particular emphasis on PGE₂, IL-1β, and TNF-α as the key mediators of alveolar bone resorption in periodontitis.
This is a shared conversation. Sign in to Orris to start your own chat.