Chemical Pathology 2 - Lipoprotein metabolism, CVD and obesity

Question 1

What is the role of HDL?

Answer 1

Picks up excess cholesterol from the periphery and transports it to liver

Question 2

What is the role of the enzyme CETP in cholesterol metabolism?

Answer 2

HDL to VLDL conversion

Question 3

What is the key enzyme involved in cholesterol synthesis?

Answer 3

HMG CoA reductase

Question 4

Which enzyme converts cholesterol to cholesteryl ester?

Answer 4

ACAT

Question 5

What is VLDL constituted of?

Answer 5

ApoB, cholesteryl ester and triglyceride

Question 6

What is the function of 7-alpha hydroxase in cholesterol metabolism?

Answer 6

Converts cholesterol to bile acids

Question 7

What is the main component of mixed micelles?

Answer 7

Bile acids

Question 8

Where are bile acids resorbed?

Answer 8

Terminal ileum

Question 9

What controls the amount of cholesterol resorbed into the intestine?

Answer 9

Balance of 2 enzymes: NPC1L1 and ABC G5/G8

Question 10

What is the inheritance pattern of familial hypercholesterolaemia type II?

Answer 10

Autosomal dominant

Question 11

What name is given to an inherited predeliction to high HDL, and what mutation causes this?

Answer 11

Familial hyper alpha lipoproteinaemia

= CETP deficiency

Question 12

What condition is caused by ABC G5/G8 mutation?

Answer 12

Phytosterolaemia

Question 13

What is phytosterolaemia?

Answer 13

Inherited condition that allows plant sterols to enter the plasma freely, which are more athrogenic than cholesterol itself

Question 14

Recall 3 clinical signs of hypercholesterolaemia

Answer 14

Xanthalasma
Arcus
Tendon xanthoma

Question 15

How can you examine for tendon xanthoma?

Answer 15

Feel back of ACL

Question 16

What are the different types of primary hypertriglyceridaemia?

Answer 16

Familial Type I: Lipoprotein lipase or apoCII def
Familial Type IV: increased synthesis of tglycerides
Familial Type V: apoAV deficiency

Question 17

What is A-beta-lipoproteinaemia?

Answer 17

MTP, apoB48, apoB100 deficiency causing hypolipidaemia (low chylomicrons, VLDL, LDL)

Results in deficiencies in fat-soluble vitamins A,D,E,K and its associated complications

Question 18

Recall 3 inherited conditions that can cause hypolipidaemia

Answer 18

A-beta-lipoproteinaemia (MTP deficiency, apoB48, apoB100 deficiencies)-very low VLDL, LDL (auto recessive)
Hypo-beta-lipoproteinaemia (truncated apoB protein)-low LDL 
Tangier disease (HDL deficiency caused by ABC1 mutation)

Question 19

What is the effect of statins on cholesterol levels?

Answer 19

Very effective at reducing LDL, also reduce triglyceride and increase HDL slightly

Question 20

What is the effect of fibrate drugs on cholesterol levels?

Answer 20

Very effective at reducing triglycerides, also increases HDL

Question 21

What is the role of PCSK9?

Answer 21

Binds LDLR and promotes its degradation

Question 22

What is the mechanism of action of statins?

Answer 22

HMG coA reductase inhibition