EXAM #1: DYSLIPIDEMIA Flashcards
What is dyslipidemia?
Preferred term to hyperlipidemia b/c of the implications of:
- High LDL
- Low HDL
- Changes in VLDL
How are cholesterol and TG transported in the blood?
Lipoprotein families
What are the subunits of a lipoprotein?
1) Lipid core of:
- TAG
- Cholesterol
- Cholesterol ester
2) Phospholipid monolayer
3) Structural apolipoproteins
What is the function of Apo B-100?
Binds to the LDL receptor
Where is Apo B-100 found?
VLDL, IDL, LDL
What is the function of Apo B-48?
Structural function
Where is Apo B-48 found?
Chylomicrons
What is the function of Apo E?
Binds LDL receptor to mediate remnant uptake
Where is Apo E found?
Chylomicrons
VLDL
IDL
HDL
What is the function of Apo C-II?
Acitivates Liporprotein Lipase
Where is Apo C-II found?
Chylomicrons
VLDLs
IDLs
What is the function of Apo A-I?
Acitivates LCAT
Where is Apo A-I found?
HDL
Where are chylomicrons made? What is the function of the chylomicron?
- Enterocytes
- Delivery of dietary TAG fatty acids to tissues
Where are VLDLs made? What is the function of VLDL?
- Liver
- Deliver TAG from the liver to extra-hepatic tissue
Where are IDLs and LDLs made? What is the function of LDL?
- Circulation
- Delivery of cholesterol and cholesterol esters to peripheral tissues
Where are HDLs made? What is the major function of HDL?
- Liver mostly, but also enterocytes
- Reverse cholesterol transport from extra-hepatic tissue to liver
What is the function of IDL?
Deliver TAG fatty acids to:
1) Extra-hepatic tissue
2) Back to liver
How is LDL taken up by the target cell?
Receptor-mediated endocytosis
What is the function of lipoprotein lipase?
Hydrolysis of TG core of:
- Chylomicrons
- VLDL
- IDL
What is the function of LCAT?
- Transfers fatty acids from lecithin to cholesterol
- Forms cholesterol ester in HDL
What is the function of CETP?
Transfer of cholesterol esters from HDL to LDL in exchange for TG, phospholipids, and cholesterol
What is the function of HMG-CoA Reductase in lipid metabolism?
HMG-CoA –> melavonic acid
*This is the rate limiting step of cholesterol biosynthesis
What is LP(a)?
LDL with an additional apolipoprotein tail attached to apoB
What is the clinical significance of LP(a)?
Increased CV risk b/c:
- Similar structure to plasminogen
- Increased inflammatory state
*Also, resistant to most diet and drug therapy
What is small dense LDL? What is the clinical importance of small dense LDL?
A subtype of LDL with smaller, denser particles
Increased arthrogenicity vs. LDL and may result in a lab underestimation of LDL burden.
How is cholesterol eliminated from the body?
Converted to bile in the liver
What was the major implication of the West of Scotland Coronary Prevention Study?
Pre-emptive statin therapy in patients with very high cholesterol prevented coronary disease
What was the major implication of the Air Force study?
Statin therapy in patients with average total cholesterol benefited from therapy
What was the major implication of the Heart Protection Study?
Treating patients with low LDL reduced cardiovascular events
What was shown about treating elderly patients with statins?
Reduced risk of MI and CVA despite age
What was shown in the study on treating diabetics with low LDL levels?
Low dose statin therapy in this high risk population was beneficial
What is the 4xS study show?
Patients with high LDL and CAD benefited from statins
What did the MIRACL study show?
Statin therapy within 96 hours post-MI prevented recurrent symptomatic ischemia
What did the study on intensive vs. standard therapy demonstrate?
High dose intense therapy reduced all-cause mortality
What determines the aggressiveness of preventive therapy in dyslipidemia?
Risk assessment independent of lipid levels
How is dyslipidemia screened for?
- Start at 20 y/o
- Every 5 years
