Chapter 13: Inflammation and Cytokines Flashcards
Leads to exposed collagen, platelet-activating factor release and tissue factor release from endothelium
Injury
What happens when platelets bind collagen?
Release growth factors (platelet-derived growth factor [PDGF]); leads to PMN and macrophage recruitment
Dominant role in wound healing; release important growth factors (PDGF) and cytokines (IL-1 and TNF-alpha)
Macrophages
- Chemotactic and activates inflammatory cells (PMNs and macrophages)
- Chemotactic and activates fibroblasts -> collagen and ECM proteins
- Angiogenesis, epithelialization, chemotactic for smooth muscle cells, has been shown to accelerate wound healing
PDGF
- Chemotactic and activates fibroblasts
- Angiogenesis
- Epithelialization
EGF (epidermal growth factor)
- Chemotactic and activates fibroblasts -> collagen and ECM proteins
- Angiogenesis
- Epithelialization
FGF (fibroblastic growth factor)
- Is not stored, generated by phospholipase in endothelium; is a phospholipid
- Chemotactic for inflammatory cells; increase adhesion molecules
PAF (platelet-activating factor)
Chemotactic factors: for inflammatory cells
PDGF, IL-8, LTB-4, C5a and C3a, PAF
Chemotactic factors: for fibroblasts
PDGF, EGF, FGF
Angiogenesis factors
PDGF, EGF, FGF, IL-8, hypoxia
Epithelialization factors
PDGF, EGE, FGF
Last 1-2 days in tissues (7 days in blood)
PMNs
Lasts 7-10 days
Platelets
Involved in chronic inflammation (T cells) and antibody production (B cells)
Lymphocytes
Growth and activating factors
PDGF, EGF, FGF, PAF, (Chemotactic, angiogenesis, epithelialization), PMNs, platelets, lymphocytes, TXA2, PGI2
- Have IgE receptors that bind to allergen
- Release major basic protein, which stimulates basophils and mast cells to release histamine
- Increased in parasitic infections
Eosinophils
What do eosinophils release?
Major basic protein, which stimulates basophils and mast cells to release histamine
Main source of histamine in blood; not found in tissue
Basophils
- Primary cell in type 1 hypersensitivity reactions
- Main source of histamine in tissues
Mast cells
- Vasodilation, tissue edema, postcapillary leakage
- Primary effector in type 1 hypersensitivity reactions (allergic reactions)
Histamine
Peripheral vasodilation, increased permeability, pain, pulmonary vasoconstriction
Bradykinin
Inactivates bradykinin; located in lung
Angiotensin-converting enzyme (ACE)
Cells involved in type 1 hypersensitivity reactions
Eosinophils, basophils, mast cells, histamine, bradykinin
Substrate for nitric oxide synthase
Arginine
Activates gauntlet cyclase and increases cGMP, resulting in vascular smooth muscle dilation
- AKA: endothelium-derived relaxing factor
Nitric Oxide (NO)
Causes vascular smooth muscle constriction (opposite effect of nitric oxide)
Endothelin
Main initial cytokine response to injury and infection
TNF-alpha and IL-1
Largest producers of TNF
Macrophages