Inflammation Flashcards
What is the role of inflammation?
- Deliver effector molecules, drugs and cells to site of infection or injury
- Induce local blood clotting
- Stimulate adaptive immune response
- Promote repair of injured tissue
What is reddness and heat during inflammation associated with?
Vasodilation: Inc blood to damage site, delivers cells etc
What is swelling and pain during inflammation associated with?
Entry of plasma proteins eg antibodies, complement components, clotting components, kinin system to extravascular space
Where do inflammatory mediators come from? What is their role?
Mast cells release inflammatory mediators which increase vasodilation
Vasoactive mediators: eg histamine
Lipid mediators: eg prostaglandins
What causes fever in inflammation?
Prostoglandins, which are released by activated mast cells
Why is pain associated with inflammation?
- Inflammatory mediators affect nocioceptors
- Bradykinin causes pain (acts on pain receptor endings)
- Exudation of plasma increases tissue pressure
How is fever initated in inflammation and how is it benefical?
- Stimulated macrophages release IL-1 (IL-6, TNF) stimulating PGE2 synthesis; acts on hypothalamus → ↑ heat production and retention
- Defences work better
- Faster lymphocyte division
- Increases cell migration
- Inhibits microbial replication
How do lipotoxins and resolvins help resolve inflammation?
- lipoxins and resolvins are secreted by macrophages, neutrophils and structural cells
They reduce: - Diapedesis
- Neutrophil chemotaxis
- Production of pro-inflammatory cytokines
- Vascular permeability
What are the stages of accute inflammation?
1) Dilation of small blood vessels
2) Increase vascular permeability
3) Endothelial cell activation and diapedeisis
4) Repair and resolution
Why is rheumothoid arthritis a chronic inflammatory disease?
Leukocytes secrete TNF-a and IL-6; which act on fibroblasts in the joints
Cytokines induce fibroblasts to produce MMP and RANK
- MMP attacks soft tissues
- RANK activates bone destroying osetoclasts
How is TB an example of partially resolved inflammation?
- Cant completely clear bacteria
- If not killed, infected macrophages are activated by IFN-y released by CD4 T cells
- Forms granuloma: TNF-a is important in maintenance
What do steroidal anti-inflammatory drugs do?
- Decrease diapedesis and inflammatory cell activation
- Decrease T-cell activation
- Decrease fibroblast function
- Decrease expression of COX-2 (prostaglandins)
- Decrease release of inflammatory mediators
- Increase release of anti-inflammatory cytokine
Why should you not treat rhuematoid arthritis with Infliximab if you have previously been diagnosed with TB?
Because infliximab gets rid of TNF-a, which is what is keeping the granulomas together so it would release a bunch of infected macrophages into your bloodstream and make you sick
