Lipid transport, apolipoproteins, dyslipidemias Flashcards

1
Q

What is the function of a chylomicron?

A

Delivers TG to peripheral tissues via LPL degradation of its TG

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1
Q

What is the function of VLDL?

A

Delivers TG to periphery; secreted by liver

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2
Q

Function of ApoC-II

A

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

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2
Q

Alcohol increases synthesis

A

HDL (in moderation)

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2
Q

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

A

TG, VLDL

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3
Q

What is the function of IDL?

A

Delivers cholesterol and TG to the LIVER

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4
Q

What is mechanism for uptake of LDL?

A

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

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5
Q

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

A

LDL and cholesterol

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6
Q

Which lipoproteins are found on VLDL?

A

ApoE, ApoC-II, ApoB-100

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7
Q

ApoC-II is found on which particles?

A

Chylomicrons, VLDL, and HDL

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7
Q

What’s the cause of familial hypercholesterolemia?

A

Absent or defective LDL receptors

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7
Q

Pancreatitis in a non-alcoholic

A

Familial hypertriglyceridemia, familial hyperchylomicronemia, hypercalcemia

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8
Q

Function of ApoA-I

A

Activates LCAT (which esterifies cholesterol)

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9
Q

Mode of inheritance:

Familial hyperchylomicronemia

Familial hypercholesterolemia

Familial hypertriglyceridemia

A

AR

AD

AD

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10
Q

Describe the transport of HDL

A

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

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11
Q

ApoB-48 is found on which particles?

A

Chylomicrons and chylomicron remnants

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13
Q

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

A

2/3

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14
Q

Pancreatitis + heptasplenomegaly + eruptive/pruritic xanthomas

A

Familial hyperchylomicronemia

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15
Q

Type I familial dyslipidemia

A

Hyperchylomicronemia

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17
Q

ApoA-I is found on which particles?

A

Chylomicrons and HDL

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18
Q

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

A

Chylomicrons, cholesterol, TG

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19
Q

Describe the transport of dietary fat and cholesterol

A

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

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20
Q

Which lipoproteins are found on HDL?

A

ApoE, ApoA-I, ApoC-II

20
Q

Secreted from liver only

Secreted from intestine only

Secreted from liver and intestine

A

VLDL

Chylomicrons

HDL

20
Q

Incidence of heterozygous familial hypercholesterolemia?

A

1:500

21
Q

Which lipoproteins are found on IDL?

A

ApoE, ApoB-100

22
Q

What causes familial hypertriglyceridemia?

A

Hepatic overproduction of VLDL

24
Q

Describe the transport of cholesterol from the liver to peripheral tissues

A

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
Q

MI at age 20

A

Homozygous familial hypercholesterolemia

26
Q

Function of ApoE

A

Uptake of all remnants except LDL

27
Q

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

A

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

28
Q

Which lipoproteins are found on chylomicron remnants?

A

ApoE, ApoB-48

29
Q

Tendon xanthoma + cholesterol ~ 300 + corneal arcus

A

Heterozygous familial hypercholesterolemia

30
Q

What is the function of HDL?

A

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

30
Q

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

A

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
Q

How is LDL formed?

A

Hepatic lipase degradation of IDL TG

34
Q

Function of HL

A

Degrades TG remaining in IDL to form LDL

36
Q

ApoB-100 is found on which particles?

A

LDL, VLDL, IDL

37
Q

Tendon xanthoma + cholesterol > 700 + corneal arcus

A

Homozygous familial hypercholesterolemia

38
Q

ApoE is found on which lipoprotein particles?

A

Chylomicrons, chylomicron remnants, HDL, VLDL, IDL

39
Q

Function of hormone-sensitive lipase

A

Degrades TG stored in adipose tissue

40
Q

What is found in lipoprotein particles?

A

Cholesterol, TG, phospholipids

42
Q

Transports cholesterol from periphery to liver

A

HDL

43
Q

Pancreatic lipase

A

Degradation of dietary TG in small bowel

44
Q

Where is LPL found?

A

Vascular endothelial surface

45
Q

What’s the cause of familial hyperchylomicronemia?

A

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

46
Q

Transport cholesterol from liver to periphery

A

LDL

47
Q

Function of ApoB-100

A

Binds LDL receptor

48
Q

Function of LPL

A

Degradation of TG in VLDL or chylomicrons

49
Q

Which lipoproteins are found on chylomicrons?

A

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

51
Q

Which is the only lipoprotein found on LDL?

A

ApoB-100 (which binds LDL receptor)

52
Q

No increased risk for atherosclerosis

A

Familial hyperchylomicronemia

53
Q

Function of ApoB-48

A

Chylomicron release

54
Q

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

A

Familial hypercholesterolemia (type IIa dyslipidemia)

55
Q

Which two lipoprotein particles carry the most cholesterol?

A

HDL and LDL