Lipids

Question 1

What does every lipoprotein contain? (4)

Answer 1

• Cholesterol
• Triglyceride
• Phospholipids
• Apolipoproteins

Question 2

What happens to ingested lipids? (4)

Answer 2

• Internalized by small bowel enterocytes
• Packaged into chylomicrons
• Transported to hepatocytes
• Endocytosed via apolipoprotein E

Question 3

What happens to cholesterol and TG in the liver?

Answer 3

packaged into very low density lipoprotein (VLDL)

Question 4

What is the function of VLDL?

Answer 4

vehicle for transport of cholesterol/TG into the bloodstream

Question 5

In the blood, what happens to the TG in VLDL?

Answer 5

• Undergoes progressive hydrolysis by endothelium bound lipoprotein lipase (LPL)
• Produces IDL and LDL

Question 6

What is the function of LDL?

Answer 6

-Main vehicle for transporting cholesterol from bloodstream to somatic cells.

Question 7

What mediates endocytosis of LDL?

Answer 7

LDL receptor and Apolipoprotein B100

Question 8

Where is HDL produced?

Answer 8

Liver

Question 9

Lipoprotein classes - Protein (%)

• Chylomicrons
• VLDL
• IDL
• LDL
• HDL

Answer 9

• Chylomicrons - 1%
• VLDL - 8%
• IDL - 15%
• LDL - 20%
• HDL - 50%

Question 10

Lipoprotein classes - Major Lipid

• Chylomicrons
• VLDL
• IDL
• LDL
• HDL

Answer 10

• Chylomicrons - TG
• VLDL - TG
• IDL - Cholesterol
• LDL - Cholesterol
• HDL - Cholesterol

Question 11

Chylomicron apolipoproteins (4)

Answer 11

• B-48
• A-1
• CII
• E

Question 12

VLDL apolipoproteins (3)

Answer 12

• B-100
• C
• E

Question 13

IDL apolipoproteins (2)

Answer 13

• B-100

- E

Question 14

LDL apolipoproteins (1)

Answer 14

-B-100

Question 15

HDL apolipoproteins (3)

Answer 15

• A-1
• C
• E

Question 16

Which lipoproteins are measured?

-Calculated?

Answer 16

• Total cholesterol
• HDL
• Triglycerides

*LDL is calculated

Question 17

VLDL is often estimated as?

• mg/dL
• mmol/L
• when is this estimation invalid?

Answer 17

VLDL is often estimated as:

• TG/5 (mg/dL)
• TG/2.2 (mmol/L)
• Estimation NOT valid:
• TG >400 mg/dL
• Chylomicrons are present

Question 18

LDL is calculated using the Friedewald Equation:

Answer 18

LDL = Total cholesterol - HDL - (TG/5)

• NOT valid:
• TG >400 mg/dL
• Chylomicrons are present
• Cholestasis

Question 19

Lipoprotein electrophoresis migration:

• chylomicrons
• LDL
• VLDL
• HDL

Answer 19

Lipoprotein electrophoresis migration:

• chylomicrons - do not move
• LDL - Beta region
• VLDL - preBeta region
• HDL - alpha region

Question 20

Overnight refridgeration produces characteristic patterns in plasma:
-Excess chylomicrons

Answer 20

Creamy layer atop the plasma

Question 21

Overnight refridgeration produces characteristic patterns in plasma:
-Turbitity or opacity of the plasma

Answer 21

Abundant VLDL

Question 22

Overnight refridgeration produces characteristic patterns in plasma:
-LDL and HDL

Answer 22

Do NOT visibly alter the plasma

Question 23

What is the most notorious consequence of hyperlipidemia?

Answer 23

Premature atherosclerosis (particularly when cholesterol (LDL/IDL) is high

Question 24

What condition features Eruptive Xanthomas (crops of yellow, pruritic papulonodules)?

Answer 24

Hypertriglyceridemia

-Chylomicrons or VDLD

Question 25

Xanthelasma (yellow periorbital papules) are associated with what?

Answer 25

High Cholesterol (LDL)

Question 26

Elevated TGs (chylomicrons or VLDL) >500 mg/dL is associated with what?

Answer 26

Acute pancreatitis

Question 27

Classification of lipid disorders by predominant lipids - Familial LPL deficiency: - Phenotype - Cholesterol - TG - Features

Answer 27

``` Familial LPL deficiency: -Phenotype - I -Cholesterol - + -TG - +++ Features: -Eruptive xanthomas -Pancreatitis ```

Question 28

Classification of lipid disorders by predominant lipids - Familial apoC-II deficiency: - Phenotype - Cholesterol - TG - Features

Answer 28

Familial apoC-II deficiency: - Phenotype - I or V - Cholesterol - + - TG - +++ - Features - Pancreatitis

Question 29

Classification of lipid disorders by predominant lipids - Familial Hypercholesterolemia: - Phenotype - Cholesterol - TG - Features

Answer 29

``` Familial Hypercholesterolemia: -Phenotype - IIa -Cholesterol - +++ -TG - + Features: -Tendinous Xanthomas -Premature Atherosclerosis ```

Question 30

Classification of lipid disorders by predominant lipids - Familial Dysbetalipoproteinemia: - Phenotype - Cholesterol - TG

Answer 30

Familial Dysbetalipoproteinemia: - Phenotype - III - Cholesterol - +++ - TG - +++

Question 31

Classification of lipid disorders by predominant lipids - Familial Combined Hyperlipidemia: - Phenotype - Cholesterol - TG - Features

Answer 31

Familial Combined Hyperlipidemia: - Phenotype - IIb or IV - Cholesterol - ++ - TG - ++ - Feature - Premature Atherosclerosis

Question 32

Classification of lipid disorders by predominant lipids - Familial Hypertriglyceridemia: - Phenotype - Cholesterol - TG - Features

Answer 32

``` Familial Hypertriglyceridemia: -Phenotype - IV or V -Cholesterol - + -TG - +++ Features: -Eruptive Xanthomas -Pancreatitis ```

Question 33

Predominant Hypercholesterolemia: - Plasma Total Cholesterol level - Lipoprotein - MC primary cause

Answer 33

- >200 mg/dL - LDL - Familial Hypercholesterolemia

Question 34

Familial Hypercholesterolemia: - Inheritance - Affect

Answer 34

- Autosomal Dominant | - Deficiency of LDL receptors or LDL receptor activity

Question 35

Secondary causes of Predominant Hypercholesterolemia? (5)

Answer 35

- Hypothyroidism - DM - Nephrotic syndrome - Cholestasis - Drugs (cyclosporine, thaizide/loop diuretics)

Question 36

Predominant hypertriglyceridemia is related to elevated?

Answer 36

Chylomicrons or VLDL

Question 37

An HDL level of what, is an independent risk factor for premature atherosclerosis?

Answer 37

<35 mg/dL

Question 38

Tangier Disease is an Autosomal Recessive disorder characterized by: - Cholesterol - TG - HDL - ApoA1 - Manifestations

Answer 38

Tangier Disease: - Low Cholesterol - Normal to increased TGs - Absent HDL - Absent ApoA1 - Cholesterol esters deposit in tonsils, LN, Vasculature, Spleen and corneal opacities

Question 39

The Third Adult Treatment Panel Report (APT III) major risk factors for coronary artery disease. (5)

Answer 39

- Smoking - HTN - Low HDL - FHx of premature CAD - Age (M<45; W<55)

Question 40

ATP III Cholesterol classification - Total: - Desirable - High

Answer 40

<200 - Desirable >240 - High

Question 41

ATP III Cholesterol classification - LDL: - Optimal - Borderline - Very high

Answer 41

ATP III Cholesterol classification - LDL: - <100 - Optimal - 130-159 - Borderline - >190 - Very high

Question 42

ATP III Cholesterol classification - HDL: - Low - High

Answer 42

<40 - Low >60 - High