SFP: atherosclerosis Flashcards
what is atherosclerosis
hardening of medium and large arteries
what is arteriosclerosis
hardening of arteries in general
what is monckeberg medial calcific sclerosis
Hardening of muscular arteries. It does not have attached clinical significance that we know of
what is arteriosclerosis
Hardening of small arteries and arterioles; often secondary to conditions like diabetes, hypertension, etc. this causes vascular changes that can further cause hypertension
What is the defining outcomes of atherosclerosis?
A mature plaque with a necrotic center containing cellular debris, solid cholesterol, (foamy) macrophages. There will also be a fibrous cap of smooth muscle cells, ECM, and new vessels via angiogenesis
What does it mean when a plaque becomes unstable? What is the concern with this?
The plaque becomes unstable when the cap deteriorates; this can lead to rupture of the plaque and hemorrhage or thrombogenesis, which can cause immediate occlusion and cell death
How does a plaque in atherosclerosis impact the surrounding vessel?
It can weaken adjacent tunica media and lead to aortic dissection or aneurysm
Atherosclerosis accounts for __% of deaths in the western world
50
Atherosclerosis can lead to which to conditions
MI and stroke
What is a large genetic risk factor for atherosclerosis
Hypercholesterolemia
In terms of cholesterol, what is found in cells of an atheroma?
Oxidized LDL
What is the structure that develops before an atheroma called?
Fatty streak
describe the formation of a fatty streak
Endothelial injury occurs, leading to endothelial dysfunction. This attracts monocytes and platelets. Smooth muscle cells also start to enter. The monocytes will become activated macrophages and begin to ingest lipids, giving them a foamy appearance
describe formation of an atheroma
The smooth muscle cells proliferate and produce more extracellular matrix, creating a stable wall around the plaque. angiogenesis also occurs and more lipids also accumulate
Describe endothelial injury and activation in the formation of a fatty streak
-Injury occurs to the endothelium, increasing its permeability
-LDL enters the intima, is oxidized, and forms various ROS and phospholipids. NO vasodilation is prevented.
-The oxidized LDL activates platelets and adhesion molecules
-Platelets bind to endothelial cells
-Macrophages ingest LDL to form foam cells
How do macrophages recruit more monocytes
Release of cytokines, chemokines, and free radicals. These further damage the endothelial system
Describe the role of T cells in forming an atheroma
Macrophages present antigens to T cells, causing them to release interferon gamma. This recruits more macrophages and c reactive protein
Why do cholesterol crystals form?
The macrophages and smooth muscle cells die, and when they do they release the LDL cholesterol they had ingested. This forms cholesterol crystals in the necrotic core of the atheroma
What medication class is thought to stabilize the plaque?
Statins; it is thought that they stabilize the fibrous cap
Describe hyaline arteriosclerosis
The lumen of the arteriole is narrowed, and the wall lacks detail. This is caused by leakage of plasma through the endothelial wall and excess ECM production. this impacts the ability of these vessels to modify their diameter. This can be seen in benign hypertension, diabetes, and elderly patients
Describe hyperplastic arteriosclerosis
Often seen in malignant hypertension. There is luminal narrowing and lamination of the vessel wall with layers of smooth muscle and thickened basement membrane. There will also be necrosis of the wall and fibrinoid deposits. These are typically known as onion skin lesions
what kind of arteriosclerosis is associated with benign hypertension
hyaline arteriosclerosis
what kind of arteriosclerosis is associated with metastatic hyperplasia
hyperplastic arteriosclerosis
what kind of arteriosclerosis is associated with “onion skin” lesions
hyperplastic arteriosclerosis
