Lipoprotein Metabolism Flashcards
Classification of lipids
- Fatty acids (palmitic, linoleic, etc)
- Glycerol esters (triglycerides)
- Sterols (cholesterol, hormones, vitamin D)
- Terpenes (vitamins A, E, K)
- Sphingosine derivates (sphingomyelin)
Explain cholesterol synthesis
Primary synthetic sites are extrahepatic, but the liver is a key regulator of homeostasis
What is the largest source of cholesterol (absorption)?
Biliary secretion
What is the normal absorption of Cholesterol?
50%
What are lipoproteins?
Molecular complexes that consist of lipids and proteins. They function as transport vehicles for lipids in blood plasma. They deliver lipid components to various tissues for use.
What are the two triglyceride-rich lipoproteins?
- Chylomicrons
- Very low-density lipoprotein (VLDL)
What are the two cholesterol-rich lipoproteins?
- LDL
- HDL
Explain LDL Cholesterol
- strongly associated with atherosclerosis and CHD events
- 10% increase results in an approximate 20% increase in CHD risk
- most cholesterol in plasma is found in LDL particles
The risk associated with LDL-C is increased by other factors, such as:
- Low serum HDL-C
- Smoking
- Hypertension
- Diabetes
Explain HDL Cholesterol
- Has a protective effect on the risk of atherosclerosis and CHD
- the lower the HDL, the higher the risk for atherosclerosis and CHD
- Tends to be low when triglycerides are high
- HDL is lowered by smoking, obesity and physical inactivity
Explain Triglycerides
- May be associated with increased risk of CHD events
- Link with increased CHD risk is complex
- May be related to:
Low HDL, highly atherogenic forms of LDL, hyperinsulinemia, hypertension, abdominal obesity
What are apolipoproteins?
- Activate enzymes involved in lipid metabolism (LCAT, LPL)
- Delivery of lipids to cells via recognition of cell surface
What are the three lipoprotein lipases?
- Pancreatic lipase
- Hepatic lipase
- Endothelial lipase
What is lipoprotein lipase?
Located in extracellular on the walls of blood capillaries. HDL-binding protein 1. LPL hydrolysed triglycerides to free fatty acids and glycerol. Free FA are transported into the tissue, mainly adipose, heart and muscle (80%). And 20% goes indirectly to the liver.
What is the pharmacotherapy to treat disorders of lipid metabolism?
- Statins: decrease cholesterol biosynthesis, upregulate LDL receptors in the liver, and increase plasma clearance of LDL.
-Fibrates: often used in combination with statins, induction of lipoprotein lipolysis, increased HDL production, increased removal of LDL particles.
-Lipid binding resins - Nicotinic acid
What is the meaning of NICE?
National Institute of Clinical Health Excellence
What are the new drugs to treat disorders of lipid metabolism?
– Ezetimibe (Ezetrol)
– PCSK9 inhibitors
What is Familial Hypercholesterolaemia?
It is a genetic condition that causes high cholesterol levels in the blood.
What are the symptoms of Familial Hypercholesterolaemia?
Fatty deposits called xanthomas on the hands, elbows, knees, ankles and around the eyes, chest pain (angina), and sores on the toes that don’t heal.
What is the treatment for Familial Hypercholesterolaemia?
- Statin drugs to lower LDL cholesterol levels
- Ezetimibe, another cholesterol-lowering medication
- LDL apheresis, a dialysis-like procedure to remove cholesterol from the blood
Triglycerides levels:
Normal: Less than 1.7 mmol/L
Borderline high: 1.7–2.2 mmol/L
High: 2.3–5.6 mmol/L
Very high: 5.7 mmol/L or higher
