Atherosclerosis Inflammation Flashcards
Define Atherosclerosis
SYSTEMIC disease of blood vessels characterized by intimal lesions called atheromas
Define Atheroma
Atherosclerotic plaque; hardening of blood vessels
Atherosclerosis is a disease of
arteries! NOT veins
Atherosclerosis Patho
Begins as a response to injury
Chronic inflammatory and healing response to injury
Lesions occur due to interaction between lipoproteins, monocytes and T cells with arterial wall
Monocytes become
Macrophages
7 Pathogenic events
Endothelial injury Accumulation of LDL and oxidation Monocyte adhesion --> macrophages --> foam cell Platelet adhesion SM cell recruitment SM cell proliferation and ECM production Further accumulation of lipids
Endothelial injury leads to
Loose tight junction = increased permeability and more adhesion molecules so things are coming in and getting stuck to the wall
SM cells
are normally in the media but they are recruited to the intima
Can proliferate and secrete ECM proteins
Oxidation
Chemical reaction where oxygen is attached to certain molecules
Lipids can interact with scavenger receptors now
Scavenger receptors
Macrophages are engulfing more and more lipids
They become full
Stimulate inflammatory mediators while dying which increases extracellular components
Two parts of atheroma
Core: filled with dying cell products
Fibrous Cap: collagen and endothelial cells
What size of fibrous cap do you want?
Thick because if it is thin it is more likely to rupture
Function of dendritic cells
Present antigen and activate T cells (without these there would be no T cell response)
Define Ulceration
Removal of the layer covering the plaque
DEEP
Erosion is
superficial
Rupture Process
SM cells, T cells and Macrophages are sitting in the plaque which it ruptures these are exposed to the blood leading to coagulation and thrombosis
Two outcomes of rupture
Thrombosis will be small and will be incorporated and healed OR thrombosis will grow and occlude the blood vessel
If you have occlusion in the coronary artery what happens?
MI
Most common cause of MI
Microvessels
Portals for entry and exit of WBC from the atheroma
As WBC enter = inflammation increase = increased risk of rupture
Also can allow blood into the plaque = swelling of the plaque = occlusion
Calcification
Deposition of calcium leads to thick, hard and stiff plaque making the blood vessel not able to respond to changes in blood pressure
Most Common Manifestations of Atherosclerosis
No symptoms (most common)
Define Compensatory enlargement
Normally narrow lumen of blood vessels increases due to occlusion
Define Stenotic occlusive disease
Blood vessel is mostly occluded
Define Aneurysm
Weakening of the blood vessel wall
