Update on lipid metabolism/CVD/obesity

Question 1

What are foam cells?

Answer 1

Macrophages full of cholesterol ester

Question 2

What is inside the necrotic core of atherosclerotic lesions?

Answer 2

Cholesterol crystals

Question 3

Which plasma lipoprotein is the main carrier of cholesterol?

Answer 3

Low density lipoprotein

Question 4

What transports cholesterol across the intestinal epithelium?

Answer 4

NPC1L1

Question 5

What transports cholesterol from the blood back into the lumen of the intestines?

Answer 5

ABC G5 and ABC G8

Question 6

What is the action of cholesterol when it arrives at the liver?

Answer 6

Downregulates the activity of HMG CoA reductase - main enzyme involved in production of cholesterol from acetate and mevalonic acid

Question 7

What are the two “fates” of cholesterol absorbed in the small intestine or produced by the liver?

Answer 7

1. Hydroxylated into bile acids

2. Esterified to produce cholesterol ether, then incorporated into VLDL particles (main precursor for LDL)

Question 8

What are HDLs responsible for?

Answer 8

Picking up excess cholesterol from the periphery

Question 9

Which transporter is important in packaging free cholesterol in the periphery into HDLs?

Answer 9

ABC A1

Question 10

Which protein mediates the movement of cholesterol/triglycerides into different types?

Answer 10

CETP - cholesteryl ester transfer protein

Question 11

What enzyme hydrolyses chylomicrons?

Answer 11

Lipoprotein lipase

Question 12

Into what are chylomicrons hydrolysed?

Answer 12

Free fatty acids

Question 13

Which genes are mutated in Familial Hypercholesterolaemia?

Answer 13

LDL receptor
ApoB
PCSK9

Question 14

What is the genetic inheritance of Familial Hypercholesterolaemia?

Answer 14

Autosomal dominant

Question 15

Which genetic condition is associated with an increase in HDL and is associated with longevity?

Answer 15

Familial hyperalphalipoproteinaemia

Deficiency of CETP

Question 16

What is the main function of ABC G5 and G8?

Answer 16

Prevent absorption of plant sterols

Question 17

Where are LDL receptors found?

Answer 17

Liver

Periphery

Question 18

What are some clinical features of Familial Hypercholesterolaemia?

Answer 18

Corneal arcus
Xanthelasma
Tendon xanthomas

Question 19

What happens in Primary Mixed Hyperlipidaemia?

Answer 19

Familial combined hyperlipidaemia

Some people will have high cholesterol and others will have high triglycerides.

Question 20

What is the pathogmonic clinical feature of Familial Dysbetalipoproteinaemia?

Answer 20

Yellow palmar crease

Question 21

List categories of causes of secondary hyperlipidaemia.

Answer 21

Hormonal
Metabolic disorders
Renal dysfunction
Obstructive liver disease
Toxins
Iatrogenic
Other

Question 22

Why does nephrotic syndrome cause secondary hyperlipidaemia?

Answer 22

Loss of protein in urine and low serum albumin switches on LDL synthesis

Question 23

What is Tangier disease?

Answer 23

HDL deficiency caused by mutation of ABC A1 (which mediates movement of cholesterol from peripheral cells into HDL)

Question 24

Which drug reduces LDL cholesterol?

Answer 24

Statins

Question 25

Which drug is good at lowering triglycerides?

Answer 25

Fibrates

Question 26

Which drug causes iatrogenic malabsorption?

Answer 26

Orlistat

Pancreatic lipase inhibitor