Lipids Flashcards
What does every lipoprotein contain? (4)
- Cholesterol
- Triglyceride
- Phospholipids
- Apolipoproteins
What happens to ingested lipids? (4)
- Internalized by small bowel enterocytes
- Packaged into chylomicrons
- Transported to hepatocytes
- Endocytosed via apolipoprotein E
What happens to cholesterol and TG in the liver?
packaged into very low density lipoprotein (VLDL)
What is the function of VLDL?
vehicle for transport of cholesterol/TG into the bloodstream
In the blood, what happens to the TG in VLDL?
- Undergoes progressive hydrolysis by endothelium bound lipoprotein lipase (LPL)
- Produces IDL and LDL
What is the function of LDL?
-Main vehicle for transporting cholesterol from bloodstream to somatic cells.
What mediates endocytosis of LDL?
LDL receptor and Apolipoprotein B100
Where is HDL produced?
Liver
Lipoprotein classes - Protein (%)
- Chylomicrons
- VLDL
- IDL
- LDL
- HDL
- Chylomicrons - 1%
- VLDL - 8%
- IDL - 15%
- LDL - 20%
- HDL - 50%
Lipoprotein classes - Major Lipid
- Chylomicrons
- VLDL
- IDL
- LDL
- HDL
- Chylomicrons - TG
- VLDL - TG
- IDL - Cholesterol
- LDL - Cholesterol
- HDL - Cholesterol
Chylomicron apolipoproteins (4)
- B-48
- A-1
- CII
- E
VLDL apolipoproteins (3)
- B-100
- C
- E
IDL apolipoproteins (2)
- B-100
- E
LDL apolipoproteins (1)
-B-100
HDL apolipoproteins (3)
- A-1
- C
- E
Which lipoproteins are measured?
-Calculated?
- Total cholesterol
- HDL
- Triglycerides
*LDL is calculated
VLDL is often estimated as?
- mg/dL
- mmol/L
- when is this estimation invalid?
VLDL is often estimated as:
- TG/5 (mg/dL)
- TG/2.2 (mmol/L)
- Estimation NOT valid:
- TG >400 mg/dL
- Chylomicrons are present
LDL is calculated using the Friedewald Equation:
LDL = Total cholesterol - HDL - (TG/5)
- NOT valid:
- TG >400 mg/dL
- Chylomicrons are present
- Cholestasis
Lipoprotein electrophoresis migration:
- chylomicrons
- LDL
- VLDL
- HDL
Lipoprotein electrophoresis migration:
- chylomicrons - do not move
- LDL - Beta region
- VLDL - preBeta region
- HDL - alpha region
Overnight refridgeration produces characteristic patterns in plasma:
-Excess chylomicrons
Creamy layer atop the plasma
Overnight refridgeration produces characteristic patterns in plasma:
-Turbitity or opacity of the plasma
Abundant VLDL
Overnight refridgeration produces characteristic patterns in plasma:
-LDL and HDL
Do NOT visibly alter the plasma
What is the most notorious consequence of hyperlipidemia?
Premature atherosclerosis (particularly when cholesterol (LDL/IDL) is high
What condition features Eruptive Xanthomas (crops of yellow, pruritic papulonodules)?
Hypertriglyceridemia
-Chylomicrons or VDLD
Xanthelasma (yellow periorbital papules) are associated with what?
High Cholesterol (LDL)
Elevated TGs (chylomicrons or VLDL) >500 mg/dL is associated with what?
Acute pancreatitis
Classification of lipid disorders by predominant lipids - Familial LPL deficiency:
- Phenotype
- Cholesterol
- TG
- Features
Familial LPL deficiency: -Phenotype - I -Cholesterol - + -TG - +++ Features: -Eruptive xanthomas -Pancreatitis
Classification of lipid disorders by predominant lipids - Familial apoC-II deficiency:
- Phenotype
- Cholesterol
- TG
- Features
Familial apoC-II deficiency:
- Phenotype - I or V
- Cholesterol - +
- TG - +++
- Features - Pancreatitis
Classification of lipid disorders by predominant lipids - Familial Hypercholesterolemia:
- Phenotype
- Cholesterol
- TG
- Features
Familial Hypercholesterolemia: -Phenotype - IIa -Cholesterol - +++ -TG - + Features: -Tendinous Xanthomas -Premature Atherosclerosis
Classification of lipid disorders by predominant lipids - Familial Dysbetalipoproteinemia:
- Phenotype
- Cholesterol
- TG
Familial Dysbetalipoproteinemia:
- Phenotype - III
- Cholesterol - +++
- TG - +++
Classification of lipid disorders by predominant lipids - Familial Combined Hyperlipidemia:
- Phenotype
- Cholesterol
- TG
- Features
Familial Combined Hyperlipidemia:
- Phenotype - IIb or IV
- Cholesterol - ++
- TG - ++
- Feature - Premature Atherosclerosis
Classification of lipid disorders by predominant lipids - Familial Hypertriglyceridemia:
- Phenotype
- Cholesterol
- TG
- Features
Familial Hypertriglyceridemia: -Phenotype - IV or V -Cholesterol - + -TG - +++ Features: -Eruptive Xanthomas -Pancreatitis
Predominant Hypercholesterolemia:
- Plasma Total Cholesterol level
- Lipoprotein
- MC primary cause
- > 200 mg/dL
- LDL
- Familial Hypercholesterolemia
Familial Hypercholesterolemia:
- Inheritance
- Affect
- Autosomal Dominant
- Deficiency of LDL receptors or LDL receptor activity
Secondary causes of Predominant Hypercholesterolemia? (5)
- Hypothyroidism
- DM
- Nephrotic syndrome
- Cholestasis
- Drugs (cyclosporine, thaizide/loop diuretics)
Predominant hypertriglyceridemia is related to elevated?
Chylomicrons or VLDL
An HDL level of what, is an independent risk factor for premature atherosclerosis?
<35 mg/dL
Tangier Disease is an Autosomal Recessive disorder characterized by:
- Cholesterol
- TG
- HDL
- ApoA1
- Manifestations
Tangier Disease:
- Low Cholesterol
- Normal to increased TGs
- Absent HDL
- Absent ApoA1
- Cholesterol esters deposit in tonsils, LN, Vasculature, Spleen and corneal opacities
The Third Adult Treatment Panel Report (APT III) major risk factors for coronary artery disease. (5)
- Smoking
- HTN
- Low HDL
- FHx of premature CAD
- Age (M<45; W<55)
ATP III Cholesterol classification - Total:
- Desirable
- High
<200 - Desirable
> 240 - High
ATP III Cholesterol classification - LDL:
- Optimal
- Borderline
- Very high
ATP III Cholesterol classification - LDL:
- <100 - Optimal
- 130-159 - Borderline
- > 190 - Very high
ATP III Cholesterol classification - HDL:
- Low
- High
<40 - Low
> 60 - High
