Chronic Inflammation Flashcards
What is the difference between chronic and and acute inflammation
Acute inflammation occurs rapidly (days) whilst chronic inflammation is persistent and can occur over months, years and years and possibly forever
What are the three main classes of chronic inflammation
1) non specific chronic inflammation
2) specific primary chronic inflammation
3) chronic granulomatous inflammation
What is non specific chronic inflammation
- failure to resolve acute inflammation
- persistent bouts of acute inflammation
- excessive suppuration
Specific (primary) chronic inflammation
- arises de novo
- persistent exposure to the agent
What is chronic granulomatous inflammation
Subset of specific chronic inflammation
What does chronic inflammation arise from
Chronic inflammation arises from acute inflammation when immune system not sufficient to eradicate stimulus
Give an example of chronic inflammation
Periodontitis
Describe chronic inflammation in terms of tissue
More tissue loss compared to acute inflammation
What are the two types of chronic inflammation
- specific chronic inflammation
- chronic granulomatous inflammation
What cells infiltrate non specific chronic inflammation
Tissue macrophages
T cells and B cells
What is non specific chronic inflammation characterised by
A dynamic balance between tissue destruction and repair
What can cause chronic inflammation
Repeated bouts of acute inflammation
Describe specific primary chronic inflammation
non granulomatous
What is specific primary chronic inflammation characterised by
Excessively activated macrophages
What is specific primary chronic inflammation induced by
Induced by - non immunological agents, foreign body reactions, inert noxious material
Induced by - immunological agents, infective organisms that grow in cells, hypersensitivity reactions, autoimmune reactions, infection by fungi, Protozoa or parasites
Describe what causes autoimmune diseases
Unwanted response to the body’s own calls and tissues or commensal bacteria
Loss (breach) of tolerance to self antigens or commensal bacteria
Multiple mechanisms of tolerance usually prevent autoimmunity
Sustained immune response generates cells and molecules that destroy tissues
What causes rheumatoid arthritis
Converted Argentine into cytokine by PAD enzyme, tis is not recognised as a self peptide therefore immune response initiated
How does chronic granulomatous inflammation differ from normal chronic inflammation
Differs from normal chronic inflammation as the predominant cell types are known as modified activated macrophages - known as epithelioid macrophages that create giant cells
T and B cells also present in the tissue
What are the causes of chronic granulomatous inflammation
Immunological - delayed hypersensitity type reaction or invading pathogens
Non immunological - foreign body in tissue eg asbestos particles
What is the main aim of macrophages in chronic inflammation
Phagocytose and present antigen
What is an M1 macrophage
Pro inflammatory
What is an M2 macrophage
Anti inflammatory
Describe what responses have macrophages have in issue injury
- toxic oxygen metabolites
- proteases
- neurophil chemotactic factors
- coagulation factors
- AA metabolites
- Nitric oxide
Describe what responses macrophages have in tissue repair
- process of fibrosis
- growth factors (PDGF,FGF,TGF, beta)
- fibrogenic cytokines
- angiogenesis factors (FGF)
- remodelling collagenases
What is orofacial granulomatosis
An example if chronic granulomatous inflammation
- effects soft tissues of the oral cavity
- id intestinal Crohn’s - termed oral Crohn’s
- no intestinal Crohn’s - terms orofacial granulomatosis
What is periodontal disease characterised by
- soft tissue destruction (gingival tissue)
- hard tissue destruction (alveolar bone)
What is RANKL
It is a ligand produced by osteoblasts that will bind to osteoclasts
What is OPG
Binds to RANKL ligand which prevents it binding to RANK (the receptor) on osteoclasts
Controlled well in normal immune system
The amount of RANKL in chronic periodontitis…
Is excessively higher that OPG being produced therefore favours bone reabsorption
What secretes osteoprotogerin (OPG)
Osteoblasts
What is bone formation called
Osteoblastogenesis
What is the ECM
Supports cells
What is the ECM remodelled by
Matrix metalloproteinses (MMPs)
What causes tissue destruction in periodontitis
- RANKL production
- Activation of osteoclasts
- reduced function of osteoclasts
- activation of MMPs
New skeleton how often
Every 10 years
