Cell Adhesion and Resolution Flashcards
What is the acute phase response characterised by?
the production of acute phase proteins by the liver and release of inflammatory cytokines
What is the acute phase response triggered by?
pro inflammatory cytokines = IL-1, IL-6 and TNF-alpha
Where are the pro inflammatory cytokines released from?
macrophages, dendritic cells
What proteins does the liver produce in response to cytokine signals?
1) C reactive protein= binds to cells and marks them for destruction
2) Serum Amyloid A= recruits immune cells to inflammatory sites and acts as an opsonin
3) Fibrinogen = promotes blood clotting to limit pathogen spread
What are the physiological changes associated with acute phase response?
1) fever = caused by inflammatory cytokines acting on hypothalamus to increase body temp
2) Leukocytosis= increased WBC
What is a consequence of chronic inflammation?
loss of function, fibrosis, scarring
What occurs during passive resolution of inflammation?
1) neutrophils migrate to site of infection and kill bacteria -> then they age and die by apoptosis
2) monocytes mature to become macrophages
3) macrophages then clear remaining bugs
What is Prostaglandin E2?
- pro inflammatory lipid mediator
- induced by cytokines IL-6/TNF-alpha
- drives vascular changes to promote inflammation = fever and pain
What is prostaglandin E2 stimulated by?
Cox enzyme
What is active resolution?
where cellular and molecular mechanisms deliberately shut down inflammation and promote tissue repair
What do neutrophils do during inflammation?
they are recruited to the site of infection and release reactive oxygen species and other microbial agents
What happens if neutrophils are not cleared?
1) they can cause tissue damage due to the release of toxic granules and enzymes -> to combat this they undergo apoptosis
2) macrophages also phagocytose neutrophils
What role do monocytes play in active resolution?
1) monocytes differentiate into macrophages via cytokines and growth factors
2) during active resolution pro inflammatory macrophages become anti inflammatory/ pro resolving macrophages
3) pro resolving macrophages secrete anti inflammatory cytokines such as IL-10 and TGF-Beta
What is the role of lipoxins in active resolution?
inhibit neutrophil infiltration into tissues
What is the function of resolvins in active resolution?
down regulate the expression of pro inflammatory cytokines and chemokines whilst up regulating anti inflammatory mediators such as IL-10
