L15: Lipids

Question 1

What are lipoproteins

Answer 1

Lipids bound to apoproteins to become transported in the blood

Question 2

What are the classes of lipoproteins

Answer 2

Chylomicrons
VLDL
HDL

Question 3

What are the 2 transport pathway of lipids

Answer 3

Exogenous

Endogenous

Question 4

Describe the process of the exogenous pathway

Answer 4

1) chylomicron goes into the lymph after enterocytes
2) chylomicron enters the blood
3) apoproteins of the chylomicron recognise the epithelial cell of adipose tissue and bind to it
4) lipoprotein lipase breaks down triglycerides in the chylomicron into fatty acids
5) fatty acids are absorbed
6) remainder of chylomicron known as chylomicron remnant goes to the liver to become absorbed

Question 5

Describe the process of the endogenous pathway of the liver

Answer 5

1) in the liver cholesterol (from exogenous pathway or from synthesis) and triglyceride is stored
2) triglyceride and cholesterol esters are released out of the liver in lipoproteins called VLDLs
3) VLDLs reach muscle and fat tissue
4) triglycerides in the VLSL are hydrolysed by lipoprotein lipase to give LDL
5) LDLs are taken bake into the liver by binding to LDL receptors on hepatocytes

Question 6

Describe the endogenous pathway process of extra-hepatic sources

Answer 6

1) epithelial cell turnover releases cholesterol
2) cholesterol is absorbed by lipoprotein called HDL
3) cholesterol esters within the HDL are transferred to LDLs
4) LDLs get taken up by hepatocytes by binding to LDL receptors

Question 7

How are cholesterol synthesised in hepatocytes

Answer 7

Acetly coA is converted to MVA by HMG coA Reductase

MVA is stored as cholesterol

Question 8

What is the most common lipoprotein that cholesterol is found in

Answer 8

LDL

Question 9

What is hyperlipidemia

Answer 9

High levels of lipids in the form of lipoproteins

Question 10

What are the types of hyperlipidemia

Answer 10

Primary

Secondary

Question 11

What is the cause of primary hyperlipidemia

Answer 11

Genetic

Question 12

What is the cause of secondary hyperlipidemia

Answer 12

Due to metabolic disorders such as diabetes, hypothyroidism

Question 13

What is the consequence of hyperlipidemia

Answer 13

Atherosclerosis

Question 14

What is atherosclerosis

Answer 14

Blood clot that affect the arteries

Question 15

What are the 7 classes of drugs that can be used to treat hyperlipidemia

Answer 15

HMG coA Reductase inhibitors 
PSK9 Inhibitors 
Fibrates
Bile-acid binding resins 
Exetimibe 
Nicotinic Acid 
Fish oil

Question 16

What is the role of HMG coA Reductase

Answer 16

1) Inhibit HMG coA reductase enzyme in the endogenous pathway to reduce cholesterol synthesis in hepatocytes
2) Reduced cholesterol synthesis increases LDL receptor transcription
3) This lowers the cholesterol levels in the blood

Question 17

What class of drug is a HMG coA Reductase

Answer 17

Statin

Question 18

Name 2 examples of statins

Answer 18

Atorvastatin

Pravastatin

Question 19

What is the role of PSK9 inhibitors

Answer 19

1) Bind to LDL receptors
2) increase LDL receptors
3) remove LDLs from the blood

Question 20

What is the role of fibrates

Answer 20

1) fibrates activate nuclear receptors
2) increase lipoprotein lipase enzyme
3) VLDLs, triglycerides decrease

Question 21

Name 2 fibrates

Answer 21

Bezafibrate

Gemfibrozil

Question 22

What is the role of bile acid binding resins

Answer 22

1) bile acid binding resins bind to bile acid
2) bile acid cannot be recycled and absorb cholesterol
3) LDL receptors increase
4) cholesterol and LDL levels decrease

Question 23

What is the role of ezetimibe

Answer 23

1) Bind to a receptor NCP1L1

2) cholesterol is not absorbed in the intestine

Question 24

What is the role of nicotinic acid

Answer 24

Reduces the levels of triglyceride in the liver

Question 25

What is the role of fish oil

Answer 25

Reduces triglyceride