mechanisms and mediators of acute inflammation Flashcards
What is the definition of acute inflammation?
Acute Inflammation is a redundant, complex, adaptative and protective response of vessels, resident cells and leucocytes to noxious stimuli.
Inflammation brings cells and molecules of host defence from the circulation to the sites where they are needed, in order to eliminate the offending agents and repair the tissues.
It lasts hours to days.
What are possible causes of acute inflammation
Infection
Microbial toxins
Tissue necrosis
Ischaemia
Trauma
Physical and chemical injury
Irradiation
Foreign bodies
Immune reactions
What are the morphological hallmarks of acute inflammation?
dilated blood vessels
activation & recruitment of leukocytes
What are the mediators in acute inflammation?
Vasoactive amines (histamine, serotonin)
Inflammatory lipids (prostaglandins, leukotrienes)
Complement (C5a, C3a)
Cytokines (IL-1, TNF, IL-6)
Where are vasoactive amines produced?
released/produced by mast cells, basophils and platelets
Where are inflammatory lipids produced?
Mast cells, leukocytes
Where are complement (C5a, C3a) produced?
Produced in the liver
Where are cytokines produced?
Macrophages, endothelial cells, mast cells
Which inflammatory mediators cause vasodilation?
Inflammatory lipids (prostaglandins, leukotrienes)
Which inflammatory mediators cause leukocyte recruitment and activation?
Inflammatory Lipids
Complement
Cytokine
Which inflammatory mediators cause increased vascular permeability?
Vasoactive amines
Complement (C5a, C3a)
Inflammatory Lipids
Cytokines (IL-1, TNF)
Which inflammatory mediator causes pain?
Inflammatory lipids
Which inflammatory mediators cause tissue damage?
Release of neutrophilic cytoplasmic content (enzymes)
Reactive oxygen species (produced by neutrophils and leukocytes)
What are the possible consequences of acute inflammation?
Complete resolution
Scarring, or fibrosis
Progression to chronic inflammation
Describe complete resolution as a result of acute inflammation
Clearance of the offending agent and regeneration of parenchymal cells with minimal tissue destruction
Describe scarring/fibrosis as a result of acute inflammation
Connective tissue growth into the area of damage or exudate when the inflammatory injury involves tissues that are incapable of regenerating, or when there is abundant fibrin exudation in tissue or serous cavities that cannot be cleared.
Occurs after substantial tissue destruction
Describe progression of acute inflammation to chronic inflammation
Unresolved inflammatory process due to either the persistence of the injurious agent or some interference with the normal process of healing.
Describe the acute phase response of inflammation
The acute phase response is characterized by different systemic effects of acute inflammation (and other conditions) including pyrexia, leucocytosis, metabolic changes. The response also includes changes in the concentrations of plasma proteins, called acute phase proteins (APPs).
Describe how acute inflammation causes pyrexia
What are the biomarkers of inflammation? positive acute phase proteins
What are the biomarkers of inflammation? negative acute phase proteins
What are the different types of exudate?
Serous
Fibrinous
Purulent
Haemorrhagic
What is a transudate?
Fluid accumulates in body cavities and extracellular compartments due to increased hydrostatic pressure and decreased colloid-osmotic pressure
