Update on lipid metabolism/CVD/obesity Flashcards
What are foam cells?
Macrophages full of cholesterol ester
What is inside the necrotic core of atherosclerotic lesions?
Cholesterol crystals
Which plasma lipoprotein is the main carrier of cholesterol?
Low density lipoprotein
What transports cholesterol across the intestinal epithelium?
NPC1L1
What transports cholesterol from the blood back into the lumen of the intestines?
ABC G5 and ABC G8
What is the action of cholesterol when it arrives at the liver?
Downregulates the activity of HMG CoA reductase - main enzyme involved in production of cholesterol from acetate and mevalonic acid
What are the two “fates” of cholesterol absorbed in the small intestine or produced by the liver?
- Hydroxylated into bile acids
2. Esterified to produce cholesterol ether, then incorporated into VLDL particles (main precursor for LDL)
What are HDLs responsible for?
Picking up excess cholesterol from the periphery
Which transporter is important in packaging free cholesterol in the periphery into HDLs?
ABC A1
Which protein mediates the movement of cholesterol/triglycerides into different types?
CETP - cholesteryl ester transfer protein
What enzyme hydrolyses chylomicrons?
Lipoprotein lipase
Into what are chylomicrons hydrolysed?
Free fatty acids
Which genes are mutated in Familial Hypercholesterolaemia?
LDL receptor
ApoB
PCSK9
What is the genetic inheritance of Familial Hypercholesterolaemia?
Autosomal dominant
Which genetic condition is associated with an increase in HDL and is associated with longevity?
Familial hyperalphalipoproteinaemia
Deficiency of CETP
What is the main function of ABC G5 and G8?
Prevent absorption of plant sterols
Where are LDL receptors found?
Liver
Periphery
What are some clinical features of Familial Hypercholesterolaemia?
Corneal arcus
Xanthelasma
Tendon xanthomas
What happens in Primary Mixed Hyperlipidaemia?
Familial combined hyperlipidaemia
Some people will have high cholesterol and others will have high triglycerides.
What is the pathogmonic clinical feature of Familial Dysbetalipoproteinaemia?
Yellow palmar crease
List categories of causes of secondary hyperlipidaemia.
Hormonal Metabolic disorders Renal dysfunction Obstructive liver disease Toxins Iatrogenic Other
Why does nephrotic syndrome cause secondary hyperlipidaemia?
Loss of protein in urine and low serum albumin switches on LDL synthesis
What is Tangier disease?
HDL deficiency caused by mutation of ABC A1 (which mediates movement of cholesterol from peripheral cells into HDL)
Which drug reduces LDL cholesterol?
Statins
