Atherosclerosis and Lipo-Protein Metabolism Flashcards
Good cholesterol?
HDL
Bad cholesterol?
LDL
Exogenous lipid metabolism pathway, mention lipase and their products
Exogenous = Absorb fats from the diet
- Amount of cholesterol taken from diet is negligible
- Dietary triglycerides and to a smaller extent cholesterol are converted into chylomicrons
- Lipases break these down leaving FFAs and chylomicron remnants
- Chylomicron remnants can contribute to atheromas
Endogenous pathway of lipid metabolism? Where does most circulating cholesterol come from?
Endogenous = generation of lipids from bodily tissues (mostly the liver)- contributes about 80% of circulating cholesterol
What enzyme converts HDL to LDL
Cholesterol ester transfer protein
What does cholesterol ester transfer protein do
Converts HDL to LDL
What is REVERSE CHOLESTEROL TRANSPORT
A process where cholesterol is taken out of blood vessels and foam cells (smooth muscle cells/macrophages which are full of lipids/cholesterol)
3 stages of atherosclerosis?
- ENDOTHELIAL DYSFUNCTION
- FATTY STREAK FORMATION
- FORMATION OF THE COMPLICATED ATHEROSCLEROTIC PLAQUE
What happens during endothelial dysfunction? (4)
- Increased permeability
- Upregulation of endothelial adhesion molecules
- Leukocyte adhesion
- Migration of leukocytes into artery wall
What happens during fatty streak formation? (5)
- Adherence and entry of leukocytes
- Migration of smooth muscle cells
- Activation of T cells
- Adherence and aggregation of platelets
- Formation of foam cells
What happens during formation of the complicated atherosclerotic plaque? (3)
- Formation of fibrous cap
- Accumulation of macrophages
- Formation of necrotic core
What is used to diagnose type of atherosclerotic plaque?
Calcium through CT scans
How does calcium relate to CVS risk
More calcium = more risk
What are remnant lipids
Remnant lipids come from breakdown of the chylomicron- they are glycoprotein containing elements which are atherogenic- increase risk of CHD
What is inflammation in atherosclerosis associated with
inflammation is associated largely with remnant cholesterol levels
Is LDL associated with inflammation?
No
What is a ‘vulnerable’ atherosclerotic plaque
‘Vulnerable’ plaques show a smaller gap between the lumen and the lipid core- this can break under high pressure and cause many problems – travel and cause thrombosis
10% increase in LDL levels results in X% increase in CHD risk
20%
How is HDL protective
promotes reverse transport and is also antioxidant to an extent
What lowers HDL?
smoking, obesity and physical inactivity
If triglycerides are high, what is the usual implication of HDL levels
Low
What do statins do to the cholesterol synthesis pathway
Statins block HMG-CoA Reductase in the cholesterol synthesis pathway
What enzyme do statins block
Statins block HMG-CoA Reductase
What cells synthesise cholesterol
Most
