Drugs affecting plasma lipids

Question 1

Plasma lipoproteins

Answer 1

HDL- takes up cholesterol from cell breakdown
LDL- cholesterol rich, taken up by liver and tissues via LDL receptor
VLDL- TG rich, transports TGs and cholesterol to muscle and adipose tissue, becomes IDL and LDL
Chlylomicrons- transport TGs and cholesterol from GI tract to liver, FFAs are released to tissues and cholesterol is stored or released to VLDL, LDL or HDL

Question 2

Risk factor for atherosclerotic disease

Answer 2

Non-HDL cholesterol (LDL, IDL and VLDL) is a major modifiable risk factor for atherosclerotic disease
Increase in atherogenic lipoproteins contribute to development of atherosclerosis
Subendothelial accumulation of LDL via LDL receptor leads to cholesterol oxidation leading to foam cell formation

Question 3

HDL-C

Answer 3

HDL transports cholesterol from peripheral tissues to the liver for excretion
HDL counteracts atherogenic actions of LDL
Raising plasma HDL concentration slows progression of atherosclerosis and may induce regression of plaques

Question 4

Triglycerides

Answer 4

Synthesis in enterocytes by re-esterification of FFAs and monoglyceride
The main storage and transport form of fat in the body, normally plasma levels rise transiently after food
Important component of lipoproteins
Often, increasing fasting TG associated with increase in LDL-C
Hypertriglyceridaemia associatd with high carbohydrate, ethanol and or high fat intake

Question 5

Defining hypercholesterolaemia

Answer 5

Ideal levels vary according to CV risk
Ideally TC <5.0mM if no risk, TC <4.0 mM if high risk or for secondary prevention
Ideally HDL-C >1.0 mM, non-HDL-C < 2.5 mM
Mild increase: 5.2-6.5 mM TC
Moderate increase: 6.5-7.9 mM TC
Severe increase >7.8 mM TC