Lipid transport, apolipoproteins, dyslipidemias Flashcards Preview

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Flashcards in Lipid transport, apolipoproteins, dyslipidemias Deck (55):
1

What is the function of a chylomicron?

Delivers TG to peripheral tissues via LPL degradation of its TG

1

What is the function of VLDL?

Delivers TG to periphery; secreted by liver

2

Function of ApoC-II

Cofactor for LPL (which degrades TG in chlyomicrons and VLDL)

2

Alcohol increases synthesis

HDL (in moderation)

2

What's elevated in the blood of a person with familial hypertriglyceridemia?

TG, VLDL

3

What is the function of IDL?

Delivers cholesterol and TG to the LIVER

4

What is mechanism for uptake of LDL?

Binds LDL receptors in periphery via B-100 and undergoes receptor-mediated endocytosis

5

What's elevated in the blood of a person with familial hypercholesterolemia?

LDL and cholesterol

6

Which lipoproteins are found on VLDL?

ApoE, ApoC-II, ApoB-100

7

ApoC-II is found on which particles?

Chylomicrons, VLDL, and HDL

7

What's the cause of familial hypercholesterolemia?

Absent or defective LDL receptors

7

Pancreatitis in a non-alcoholic

Familial hypertriglyceridemia, familial hyperchylomicronemia, hypercalcemia

8

Function of ApoA-I

Activates LCAT (which esterifies cholesterol)

9

Mode of inheritance:

Familial hyperchylomicronemia

Familial hypercholesterolemia

Familial hypertriglyceridemia

AR

AD

AD

10

Describe the transport of HDL

Nascent HDL particles released by the liver and intestine --> acted on by LCAT which esterifies cholesterol --> forms mature HDL --> goes back oto the liver or is acted on by CETP --> transfers cholesterol esters to other lipoprotein particles

11

ApoB-48 is found on which particles?

Chylomicrons and chylomicron remnants

13

What proportion of plasma cholesterol is esterified by LCAT to form mature HDL?

2/3

14

Pancreatitis + heptasplenomegaly + eruptive/pruritic xanthomas

Familial hyperchylomicronemia

15

Type I familial dyslipidemia

Hyperchylomicronemia

17

ApoA-I is found on which particles?

Chylomicrons and HDL

18

What's elevated in the blood of a person with familial hyperchylomicronemia?

Chylomicrons, cholesterol, TG

19

Describe the transport of dietary fat and cholesterol

Formed into chylomicrons in the small intestine with the aid of bile acids from the liver --> acted on by LPL on surface of vascular endothelium --> releases FFA that go to skeletal muscle and adipose tissue --> chylomicron remnants taken up by liver via chylomicron remnant receptors

20

Which lipoproteins are found on HDL?

ApoE, ApoA-I, ApoC-II

20

Secreted from liver only

Secreted from intestine only

Secreted from liver and intestine

VLDL

Chylomicrons

HDL

20

Incidence of heterozygous familial hypercholesterolemia?

1:500

21

Which lipoproteins are found on IDL?

ApoE, ApoB-100

22

What causes familial hypertriglyceridemia?

Hepatic overproduction of VLDL

24

Describe the transport of cholesterol from the liver to peripheral tissues

VLDL made in and released by the liver into circulation --> acted on by LPL bound to vascular endothelium --> forms FFA + IDL which goes back to the liver or is acted upon by HL --> forms LDL --> taken up by LDL receptors in liver or peripheral tissues

25

MI at age 20

Homozygous familial hypercholesterolemia

26

Function of ApoE

Uptake of all remnants except LDL

27

What is a chylomicron remnant made up of and what is its function?

Cholesterol, most of its TG has been depleted; delivers cholesterol to the liver (uptake via ApoE)

28

Which lipoproteins are found on chylomicron remnants?

ApoE, ApoB-48

29

Tendon xanthoma + cholesterol ~ 300 + corneal arcus

Heterozygous familial hypercholesterolemia

30

What is the function of HDL?

Transports cholesterol from periphery to liver and provides a reservoir of ApoE and ApoC, which are needed for VLDL and chylomicron metabolism

30

Young non-drinker with pancreatitis that resolves rapidly upon fasting + normal gallbladder US

Hypertriglyceridemia

 

(TG + pancreatic lipase = FFA in pancreatic capillaries; normally these FFA bind albumin but if TG > 1000 albumin becomes overwhelmed and FFA cause direct damage to pancreas)

32

How is LDL formed?

Hepatic lipase degradation of IDL TG

34

Function of HL

Degrades TG remaining in IDL to form LDL

36

ApoB-100 is found on which particles?

LDL, VLDL, IDL

37

Tendon xanthoma + cholesterol > 700 + corneal arcus

Homozygous familial hypercholesterolemia

38

ApoE is found on which lipoprotein particles?

Chylomicrons, chylomicron remnants, HDL, VLDL, IDL

39

Function of hormone-sensitive lipase

Degrades TG stored in adipose tissue

40

What is found in lipoprotein particles?

Cholesterol, TG, phospholipids

42

Transports cholesterol from periphery to liver

HDL

43

Pancreatic lipase

Degradation of dietary TG in small bowel

44

Where is LPL found?

Vascular endothelial surface

45

What's the cause of familial hyperchylomicronemia?

Defective lipoprotein lipase or ApoC-II (LPL cofactor) = can't degrade TG in chylomicron to for chylomicron remnants for uptake by liver

46

Transport cholesterol from liver to periphery

LDL

47

Function of ApoB-100

Binds LDL receptor

48

Function of LPL

Degradation of TG in VLDL or chylomicrons

49

Which lipoproteins are found on chylomicrons?

ApoE, ApoB-48, ApoA-I, ApoC-II

51

Which is the only lipoprotein found on LDL?

ApoB-100 (which binds LDL receptor)

52

No increased risk for atherosclerosis

Familial hyperchylomicronemia

53

Function of ApoB-48

Chylomicron release

54

Dx if this is a 25-year-old patient?

Familial hypercholesterolemia (type IIa dyslipidemia)

55

Which two lipoprotein particles carry the most cholesterol?

HDL and LDL