Lipid Metabolism and CVD Flashcards
what are the 2 key lipids
- cholesterol
- triacylglyceride
how likely are you to come across key lipids clinically
- Xanthomata
- Xanthelasma
- Corneal arcus
- Milky blood/serum
how likely are you to come across key lipids As cardiovascular disease risk factor
- Coronary heart disease
- Cerebrovascular disease
- Peripheral vascular disease
- As risk factor for acute pancreatitis (triglycerides)
when are lipids measured in practise
- Total cholesterol (HDL + LDL + VLDL)
- HDL cholesterol
- Triglycerides as requested
- We calculate the total/HDL cholesterol ratio
- LDL cholesterol calculated as requested – if possible
what are transported in the blood within lipoproteins
non-polar lipids
what are lipoproteins
microscopic spherical particles consisting of:
- Hydrophobic core containing esterified cholesterol and triglycerides
- Hydrophilic coat comprising a monolayer of amphipathic cholesterol, phospholipids and one or more apoproteins
what are apoproteins
they allow lipoproteins to bind to cells
- are recognized by receptors in the liver and other tissues
how many classes of lipoproteins are there?
4
what are the 4 classes of lipoproteins
- HDL particles: contain apoA-I and apoA-II
- LDL particles: contain apoB-100
- VLDL (very low-density lipoprotein): contain apoB-100
- Chylomicrons: contain apoB-48
what do ApoB-containing lipoproteins do
Deliver TAGs to muscle for ATP biogenesis and adipocytes for storage
what is LDL clearance dependent on
LDL receptors expressed by liver (most important) and other tissues
what does Cellular uptake of LDL particles occurs via
receptor mediated endocytosis
Within the cell, what is cholesterol released from
cholesteryl ester by hydrolysis
what is the cause of Cardiovascular disease (atherosclerosis) cuased by elevated LDL and decreased HDL
diet
lifestyle
genetic factors
Increased LDL →
pathogenesis of atherosclerosis
what does HDL do
accepts excess cholesterol from plasma membrane of cells (e.g. macrophages) and delivers it to liver - reverse cholesterol transport
what is the only organ that can remove cholesterol
the liver
mechanism of action for statins
Block denovo synthesis of cholesterol, causing liver to upregulate LDL receptors
what else do statins do other than lowering cholesterol
- Blocks pathway for producing cholesterol
- Act as competitive inhibitors of HMG-CoA reductase - rate limiting step in cholesterol synthesis in hepatocytes
- less cholesterol in cell
- Decrease in hepatocyte cholesterol synthesis causes a compensatory increase in LDL receptor expression and enhanced clearance of LDL
what else does cholesterol prevent
- smooth muscle migration
- foam cell formation
- T cell activation
- adherance and aggregation of platlets and leukocytes
