Pharm Hyperlipidemias Flashcards
What is the MOA of statins?
HMG-CoA reductase inhibitor that blocks the rate-limiting step in cholesterol synthesis
What is the primary effect of statin therapy?
lowers LDL by 25-60%
What is the MOA of bile acid resins? Name them.
binds to bile acid to prevent re-absorption and re-use of bile acid cholesterol
Colestipol, cholestyramine, and colesevelam
What is the primary effect of bile acid resins?
lowers LDL by up to 20%
What is the MOA of ezetimibe?
prevents the aborption of dietary cholesterol
What is the primary effect of ezetimibe?
lowers LDL by up to 20%
What is the MOA of niacin?
inhibits VLDL secretion, in turn decreasing production of LDL. Increased clearance of VLDL via the LPL pathway contributes to reduction of triglycerides.
What is the primary effect of niacin?
Decreases LDL levels by about 20% and TGs. It often increases HDL levels significantly.
Where does micelle formation occur?
in the small interstine
Where are micelles absorbed to make chylomicrons?
intestinal mucosal cells
What are the 4 components of a nascent chylomicron?
o Phospholipids o Triacylglycerols (80-95%) o Cholesterol o Apoprotein B-48 * 10:1 TG: cholesterol ratio
Where do nascent chylomicrons enter the blood?
thoracic duct
What happens when nascent chylomicrons come in to contact with HDL in the blood?
HDL donates ApoCII and ApoE to the nascent chylomicron which is then called a mature chylomicron.
What is the fate of a mature chylomicron?
The ApoCII on mature chylomicrons binds to Lipoprotein Lipase on tissues which allows TGs in the lipoprotein to be broken down. The free fatty acids and diglycerides are taken in to the adjacent tissue cell to be utilized or stored.
How is a chylomicron remnant formed?
ApoCII is given back to HDL and the chylomicron is now called a remnant.
What is the fate of a chylomicron remnant?
The remnant is then further acted upon by LPL and Hepatic lipase to form a particle that is taken up by the liver via an ApoE receptor.
What are remnant components used for in the liver?
The remnant’s components are then used to synthesize nascent VLDL
How does nascent VLDL mature?
Nascent VLDL comes into contact with HDL in the blood and acquired the ApoCII and ApoE to become mature
What are the components of VLDL?
• Apoprotein B100 (backbone of lipoprotein) • TGs (55-80%) • Cholesterol • Phospholipids *5:1 TG: cholesterol ratio
How is IDL formed?
The ApoCII on mature VLDL binds to Lipoprotein Lipase on tissues which allows TGs in the lipoprotein to be broken down. VLDL then donates ApoCII back to HDL and becomes IDL
What is the TG: cholesterol ratio of IDL?
1:1
How is LDL formed?
As IDL loses TGs and becomes less dense, it is considered to be a LDL
What is the fate of LDL?
LDL is then catabolized by hepatocytes and other cells via receptor-mediated endocytosis (LDL receptor) BUT usually goes to periphery and stores (in things like arteries—causing problems)
What makes up LDL?
(low TG content, high cholesterol content).
Describe HDL synthesis? *he didn’t talk about this is class
- Early HDL (with ApoA1) is generated in liver. It is released from the liver and picks up free cholesterol from periphery (via ABCG1 and ABCA1)
- This cholesterol in the core of the HDL is esterified by LCAT to form cholesteryl esters
- Cholesterylester transfer protein (CETP) facilitates the transfer of cholesterol esters (in HDLs) with TAGs (in VLDLs and LDLs). This makes the HDL larger and more susceptible to uptake by the liver.
- These HDL particles can be taken up by Scavenger Receptor-B1 (on liver)
What causes Primary chylomicronemia?
Defective removal of CM (apoCII, LPL defect)
What is the effect of primary chylomicronemia?
Chylomicrons elevated, VLDL elevated, pancreatitis
What does serum of a patient with primary chylomicronemia look like?
creamy layer and clear infranate
What causes Familial hypertriglyceridemia?
Defective metabolism of VLDL (LPL defect)
What is the primary effect of Familial hypertriglyceridemia?
VLDL elevated, Hypertriglyceridemia, pancreatitis
Who do you typically see with Familial hypertriglyceridemia? How do you treat it?
Classic in people with T2D with low insulin! Develop LPL defect. Treat the diabetes, and put patient on low calorie diet.
What does serum of a patient with Familial hypertriglyceridemia look like?
Will see creamy layer with cloudy infranate
What causes Familial dysbetalipoproteinemia?
Defective metabolism of VLDL, Chylomicrons, ApoE defect (E2/E2 alleles that are not as good at binding to ApoE receptor!).
What is the primary effect of Familial dysbetalipoproteinemia?
VLDL and CM remnants (IDL) elevated. Cholesterol and TG elevated 1:1, atherosclerosis
What causes Familial Combined Hyperlipidemia (FCH)?
Overproduction of apoB (VLDL)