Atherosclerosis and LDL

Question 1

What are lipoproteins

Answer 1

Carry cholesterol in the blood. Contain apoproteins on the surface with a phospholipid membrane, triglycerides on the inside and Cholesterol is embedded into the protein.

Question 2

Structure of HDL vs LDL vs VLDL

Answer 2

HDL is mostly protein with little cholesterol and triglyceride. LDL has the same amount of triglyceride as HDL but more cholesterol and less protein. VLDL has lots of triglyceride and cholesterol with little protein.

Question 3

Explain where LDL comes from

Answer 3

The liver releases vLDL which is broken down by LPL into remnants and LDL. LDL is cleared from plasma by LDL receptor on peripheral tissues

Question 4

Explain liver regulation of cholesterol

Answer 4

Cholesterol is delivered to the liver by 2 methods, extrahepatically synthesized cholesterol or LDL particles which bind to LDL receptors on liver. Cholesterol leaves the liver by two methods, secretion in the form of VLDL (most of which returns to liver in form of LDL) or excretion into bile. The liver regulates the amount of excretion of cholesterol into bile and regulates the number of LDL receptors to take up LDL

Question 5

How does an atherosclerotic plaque develop

Answer 5

LDL, VLDL remnants and chylomicron remnants from circulation migrate through arterial endothelium into intima > monocytes are recruited to intima > develop into macrophages> Take up lipoprotein particles >foam cells > foam cells induce smooth muscle proliferation, thickening of intima > plaque

Question 6

What were the old guidelines for CVD?

Answer 6

Joint national committee (JNC7) had regulations on blood pressure. ATP4 had regulations on blood cholesterol

Question 7

How do you determine the levels of VLDL, HDL, and LDL

Answer 7

VLDL: triglycerides /5 (if TG <400mg/dl). LDL= total cholesterol - (TG/5) - (HDL)

Question 8

According to old regulations, what are the LDL goals for High, moderately high, moderate and low CHD risk patients

Answer 8

High: <160

Question 9

risk factors for coronary heart disease

Answer 9

Age (men >45, women >55), tobacco, HTN (>140/90), family history (1st degree male (<40

Question 10

Which groups benefit from statins

Answer 10

High risk groups with evidence of CV disease, anyone with LDL >190, 40-75yrs with diabetes and LDL 70-189, primary prevention in 40-75yrs with LDL 70-189 and risk >7.5%

Question 11

How do statins lower CVD risk

Answer 11

Plaque lesions become more fibrotic and stable. Also inflammation is decreased