Lipoprotein Disorders

Question 1

How are diet derived TGs transported in the blood?

Answer 1

Chylomicrons

Question 2

How are diet derived TGs transported in the blood?

Answer 2

Chylomicrons

Question 3

What is the least dense lipoprotein?

Answer 3

Chylomicrons

Question 4

Enterocytes lining villi reabsorb monoglycerides and FAs which are converted into TGs in the cytosol. TGs are then packed into a chylomicron and require an apolipoprotein for asseblym/secretion. What apolipoprotein is required?

Answer 4

apoB48

Question 5

Where do chylomicrons enter the blood stream?

Answer 5

Thoracic duct

Question 6

How do nascent chylomicrons become mature chylomicrons?

Answer 6

Obtain apoE/apoC2 from HDL

Question 7

What enzyme hydrolyzes TGs in chylomicrons?

Answer 7

Lipoprotein lipase

Question 8

What is the function of apoC2 and apoE with regards to chylomicrons?

Answer 8

apoC2: activates LPL
apoE: removes chylomicrons remnants from the circulation

Question 9

Where is VLDL synthesized?

Answer 9

Liver

Question 10

What apolipoprotein is necessary for TG to be packaged into VLDL and secreted into the blood?

Answer 10

apoB100

Question 11

VLDL is hydrolyzed by LPL. What are the lipoprotein products formed by this reaction?

Answer 11

IDL, and LDL

Question 12

What is cholesterol ester transport protein (CETP)?

Answer 12

Transfers cholesterol from HDL to VLDL in exchange for TG- leads to removal of HDL from circulation

Question 13

What is the optimal serum TG level?

Answer 13

Less than 150 mg/dL

Question 14

What is a high serum TG level?

Answer 14

Greater than 200 mg/dL

Question 15

TG/5 = ?

Answer 15

VLDL

Question 16

Enterocytes lining the villi reabsorb monoglycerides and FAs which are then converted into TG in the cytosol. TGs are then packed into a chylomicron and require an apolipoprotein for asseblym/secretion. What apolipoprotein is required?

Answer 16

apoB48

Question 17

Nascent chylomicrons enter the intestinal lymphatics, where do chylomicrons enter the blood stream?

Answer 17

Thoracic duct

Question 18

How do nascent chylomicrons become mature chylomicrons?

Answer 18

Obtain apoE/apoC2 from HDL

Question 19

What enzyme hydrolyzes TGs in chylomicrons?

Answer 19

Lipoprotein lipase

Question 20

What is the function of apoC2 and apoE with regards to chylomicrons?

Answer 20

apoC2: activates LPL
apoE: removes chylomicrons remnants from the circulation

Question 21

Where is VLDL synthesized?

Answer 21

Liver

Question 22

What apolipoprotein is necessary for TG to be packaged into VLDL and secreted into the blood?

Answer 22

apoB100

Question 23

What effect does VLDL levels have on HDL levels?

Answer 23

Increased VLDL causes decreased HDL

Question 24

What are the functions of HDL?

Answer 24

Source of apolipoproteins for other lipoproteins (apoE,C2)

Removes CH from fatty streaks and atherosclerotic plaques

Question 25

What pathology is due to a deficiency of apoE?

Answer 25

Type 3 hyperlipoproteinemia (broad beta disease)- build up of chylomicron remnants

Question 26

What would a 16 hour standing test show for a patient with familial hyperchylomicronemia?

Answer 26

Turbid supranate

Question 27

Detail the pathogenesis of genetic type 2a hyperlipoproteinemia (familial hypercholesterolemia).

Answer 27

AD inheritance of deficient LDL receptors

Question 28

Increased serum TGs is due to an increase in chylomicrons and/or VLDL. How can you differentiate which lipoprotein component is elevated?

Answer 28

Standing chylomicron test- test tube is left in a refrigerator overnight to give TG a change to settle based on density

Question 29

What physical exam findings are characteristic of familial hypercholesterolemia?

Answer 29

Achilles tendon xanthoma | Xanthelasma

Question 30

What is LDL derived from?

Answer 30

VLDL

Question 31

LDL=?

Answer 31

CH-HDL-TG/5

Question 32

Why is fasting required to accurately calculate LDL?

Answer 32

Increased chylomicrons falsely lower calculated LDL

Question 33

Small dense LDL particles are associated with increased risk of what disease(s)?

Answer 33

Atherosclerosis, CAD

Question 34

What is the function of cholesterol?

Answer 34

Synthesis of: vitamin D, adrenal cortex hormones, bile

Question 35

What is the optimal serum LDL level?

Answer 35

Less than 100

Question 36

What increases HDL?

Answer 36

Niacin (nicotinic acid), exercise

Question 37

Detail the pathogenesis of type 1 hyperlipoproteinemia (familial hyperchylomicronemia)

Answer 37

AR inheritance of deficient LPL or apoC2

Question 38

What are the clinical findings of familial hyperchylomicronemia ?

Answer 38

Pancreatitis

Question 39

Detail the pathogenesis of genetic type 2a hyperlipoproteinemia (familial hypercholesterolemia).

Answer 39

AD inheritance of deficient LDL receptors.

Question 40

What does a lipid profile show for a patient with familial hypercholesterolemia?

Answer 40

Elevated CH and LDL, decreased HDL

Question 41

What physical exam findings are characteristic of familial hypercholesterolemia?

Answer 41

Achilles tendon xanthoma | Xanthelasma

Question 42

Detail the pathogenesis of type 3 hyperlipoproteinemia (broad beta disease).

Answer 42

AR inheritance of deficient apoE

Question 43

Patients who are homozygotes for type 2 hyperlipoproteinemia are at an increased risk for having an MI before what age?

Answer 43

20

Question 44

What physical exam finding is characteristic of broad beta disease?

Answer 44

Palmar xanthomas in flexor creases

Question 45

Detail the pathogenesis of genetic type 4 hyperlipoproteinemia (familial hypertriglyceridemia).

Answer 45

AD inheritance resulting in overproduction of VLDL

Question 46

What physical exam finding is characteristic of type 4 hyperlipoproteinemia?

Answer 46

Eruptive xanthomas

Question 47

What hyperlipoproteinemias can present with acute pancreatitis?

Answer 47

Type 4- familial hypertriglyceridemia | Type 1- familial chylomicronemia

Question 48

What are acquired causes of type 2 hyperlipoproteinemia?

Answer 48

Hypothyroidism- decreased LDL receptor synthesis | Nephrotic syndrome- increased VLDL synthesis

Question 49

What are acquired causes of type 4 hyperlipoproteinemia?

Answer 49

Excess EtOH- increased VLDL production OCPs- increased VLDL production DM- decreased LPL due to decreased insulin

Question 50

A standing chylomicron test distinguishes which lipoprotein component is increased. Detail possible outcomes.

Answer 50

Turbid supernate- increased chylomicrons (person did not fast, type 1 hyperlipoproteinemia) Infranate- increased VLDL (type 4 hyperlipoproteinemia) Turbid Supranate + infranate- increased chylomicrons and VLDL (type 5 hyperliproteinemia)