Lipoproteins II

Question 1

……. is filled in the blood with cholesteryl esters which are delivered back to the liver.

Answer 1

HDL

Question 2

HDLs act as a “reservoir” of ……. and ……which are transferred to chylomicrons and VLDL.

Answer 2

Apo- E and Apo-C

Question 3

This enzyme is synthesized in hepatocytes and released into the blood and forms cholesteryl esters

Answer 3

Lecithin-cholesterol-acyl transferase (LCAT or PCAT)

Question 4

HDL3 is changed to the larger ……….after uptake of more cholesterol esters

Answer 4

HDL2

HDL2 interact via CETP (cholesteryl ester transfer protein) with VLDL

Question 5

HDL2 binds to the scavenger receptor ……. and the cholesteryl esters in HDL are equilibrated with the intracellular cholesteryl esters.

Answer 5

SR-B1

Question 6

The smaller HDL leaves the hepatic SR-B1 and can be filled in the …….again with cholesteryl esters.

Answer 6

Blood

Question 7

LCAT needs activation by ……. and binds to HDL

Answer 7

Apo A-1

Question 8

The transfer of a fatty acid from phosphatidylcholine (lecithin) from the HDL membrane to free cholesterol is catalyzed by …… in the blood.

Answer 8

LCAT

Question 9

Free cholesterol is provided by the plasma membrane cholesterol ……… transporter

Answer 9

ABCA1

Question 10

…… is a protein in the blood that can form a bridge between VLDL and HDL which allows the movement of cholesteryl esters (CE) from HDL into VLDL in exchange for TAGs

Answer 10

CETP

Question 11

CE exchanged from HDL can reach the liver via ………. and aid with the reverse cholesterol transport

Answer 11

IDL or LDL

Question 12

Hypoalphalipoproteinemia:

Answer 12

Low HDL and low Apo A-1 levels

Question 13

Abetalipoproteinemia: a rare hereditary disease caused by an abnormal MTP (microsomal TAG transfer protein) results in ….

Answer 13

No or low LDL

Question 14

Rare hereditary disease characterized by orange colored tonsils in children and accumulation of cholesteryl esters in liver or spleen due to extremely low HDL.

Answer 14

Tangier Disease (example of a Hypoalphalipoproteinemia)

Question 15

The very low HDL levels in Tangier Disease result from the degradation of ……. and deficiency of the cholesterol transporter……

Answer 15

Apo A-1

ABCA1

Question 16

All are characteristics of which disease?

• Strongly reduced release of VLDL and chylomicrons
• Blood TAG levels <19 mg/dL (normal 150)
• Total cholesterol <50 mg/dL (normal 200)
• Failure to thrive. Fat malabsorption
• TAG accumulation in liver and intestine

Answer 16

Abetalipoproteinemia: MTP deficiency

Question 17

What are the normal levels of LDL, HDL, and VLDL in the blood?

Answer 17

LDL- 100-130
HDL- 40-70
VLDL- 20-30

Question 18

…………refers to an abnormal lipoprotein pattern that is risk factor for cardiovascular disease (CVD):

1. High total cholesterol > 200 mg/dL
2. High LDL-C > 160 mg/dL
3. High TAG > 200 mg/dL
4. Low HDL-C < 40mg/dL

Answer 18

Dyslipidemia

Question 19

Friedewald Equation: Lipid profile for screening for CVD risk factors

Answer 19

[LDL-C] = [total C] – ( [HDL-C] +[TAG: 5] )

Question 20

Type I: Familial Hyperchylomicronemia

Answer 20

Rare disease characterized by a high serum TAG level (>750 mg/dL) caused by a high chylomicron level. Creamy layer on top of blood sample

Question 21

Patients with Type I: Familial Hyperchylomicronemia present with:

Answer 21

Xanthomas, Hepatosplenomegaly, lipemia retinalis (vessels creamy white)

Question 22

Type IIa: Familial Hypercholesterolemia

Answer 22

High LDL, normal VLDL and clear serum.
Total cholesterol 250-500 mg/dL
Tendon Xanthomas and Xanthelasma near eyelids

Question 23

Cause of Type IIa: Familial Hypercholesterolemia is mainly a defect in ………..

Answer 23

LDL receptor or clearance of LDL (Apo-100)

Question 24

Type IIb: Familial Combined Hyperlipidemia

Answer 24

High LDL, high VLDL and turbid serum
Total cholesterol: 250-500 mg/dL
TAG 250-750 mg/dL

Question 25

– Overproduction of apo B100
– Overproduction of VLDL
– Defective clearance of LDL may be the cause of …………

Answer 25

Type IIb: Familial Combined Hyperlipidemia

Question 26

Type III: Dysbetalipoproteinemia:

Answer 26

High remnant levels (chylomicron remnants and IDL) but also abnormal b-VLDL

• Total cholesterol 250-500 mg/dL
• TAG 250-500 mg/dL

Question 27

Deficiency in Apo-E resulting in palmar xanthomas and tuber-eruptive xanthomas over the elbows and knees are characteristic of…..

Answer 27

Type III: Dysbetalipoproteinemia

Question 28

Type IV: Familial Hyperprebetalipoproteinemia:

Answer 28

High VLDL

TAG 200-500 mg/dL

Question 29

High VLDL levels in Type IV may be caused by

Answer 29

LPL deficiency or overproduction of VLDL

Question 30

Type V: Familial Mixed Hypertriacylglyerolemia

Answer 30

High chylomicron levels

High VLDL levels.

Question 31

What is the concept to treat hypercholesterolemia?

Answer 31

Reduction of hepatic cytosolic cholesterol with statin drugs (inhibit hepatic cholesterol synthesis) which increases of LDL-receptors and LDL-clearance.

Question 32

What is another concept to treat hypertriacylglyerolemia?

Answer 32

Reduction of hepatic TAG synthesis which leads to lower levels of VLDL, LDL and elevates HDL level with niacin and fibrates

Question 33

LDL pattern …… is considered a risk factor for CHD (coronary heart disease)

Answer 33

LDL pattern B

Question 34

……….. is a risk for coronary heart disease because it may reduce the removal of blood clots which could trigger MI or stroke.

Answer 34

Lipoprotein A