Cardiovascular: Lipids and CV Disease

Question 1

Important lipids on CV disease

Answer 1

Cholesterol

Triglycerides

Question 2

What is the function of lipoproteines

Answer 2

They transport cholesterol and triglycerides around the body

Question 3

Deacreasing order of size of lipoproteins

Answer 3

Largest

3. 1. Chylomicrons
4. Very Low Density Lipoprotein (VLDL)
5. Intermediate Density Lipoprotein (IDL)
6. Low Density Lipoprotein (LDL)
7. High Density Lipoprotein (HDL)

Smallest

Question 4

Three main pathways of lipid metabolism and transport

Answer 4

Question 5

What is Lipoprotein lipase (LPL)

Answer 5

Lipoprotein lipase (LPL) is an enzyme on the vascular endothelial surface that degrades circulating triglycerides in the bloodstream into non-esterified fatty acids (NEFAs) which can be used in metabolism

These are triglycerides carried by VLDL and Chylomicrons

The example below if the exogenous lipid pathway

Question 6

What happens if you are deficient in LPL

Answer 6

You get a build up of chylomicrons

Question 7

Describe the role of LPL and the various lipoproteins in the endogenous lipid pathway

Answer 7

Question 8

Describe the reverse lipid pathway

Answer 8

Question 9

Describe how the roles of the vareous lipoproteins vary

Answer 9

• Chylomicrons -biggest, mostly triglycerides - involved in exogenous lipid pathway
• Very Low Density Lipoprotein (VLDL), quite big, pred. triglycerides - endogenous
• Intermediate Density Lipoprotein (IDL) - more like a breakdown of VLDL
• medium-sized, very short lived -more like a breakdown of VLDL
• Low Density Lipoprotein (LDL), small, cholesterol-rich, long-lived, take cholesterol to peripheries
• High Density Lipoprotein (HDL), smallest, cholesterol-rich, long-lived, take cholesterol back to liver

Question 10

How does LPL differ from LCAT

Answer 10

LPL is the enzyme that removes lipid from lipoproteins

LCAT is the enzyme that attaches choloesterol to HDL

Question 11

What can go back to the liver?

Answer 11

Cholesterol and not triglycerides

Question 12

Where do triglycerides go vs cholesterol?

Answer 12

Tryglycerides go to muscle and adipose tissue

Cholesterol goes to peripheral tissue

Question 13

What is worse for you? LDL-cholesterol or HDL-cholesterol?

Answer 13

LDL-choloesterol increases risk of CV disease where HDL-choloesterol decreases it.

This is because HDL-cholesterol will be more inclined ot go back to the liver

Question 14

Describe the process of how an atheroma forms on the inside of a vessel?

Answer 14

First LDLs are oxidised by O-radical (smoking)

Then macrophages don’t like these and eat them up become lipid laden foam cells

The macrophages trigger the smooth muscle cells to be fibritic creating a fibrous collegen cap

Underneath these the macrophages undergoes apoptosis leaveing behind lipid underneath a fibrous cap - an atheroma

Question 15

What happens when an atheroma ruptures?

Answer 15

Question 16

What are the three steps leading to lipid driven ischeamia

Answer 16

1. Fatty streak formation (build up of foam cells witin arterial wall)
2. Atheroma formation from response to foam cells
3. Rupture leading to complete blockage (or sometimes if it fibrous enough it won’t rupture instead becoming a stable angina)

Question 17

What is familial hypercholesterolaemia?

Answer 17

A mutation in the LDL receptor resulting in unusually high levels of LDL-C

Question 18

3 Signs of familial hypercholesterolaemia

Answer 18

Question 19

What do statins do?

Answer 19

Reduce LDL-cholesterol