Lipid Physiology

Question 1

Lipoprotein

• structure
• types

Answer 1

PL, cholesterol
TAG, cholesterol ester core

Chylomicrons - least dense, most TAGs
LDL
HDL - most dense, least TAGs

Question 2

Functions of lipids

Answer 2

TAG - Energy transport
Cholesterol - membrane components
ADEK - vitamin transport

Question 3

Function of

• chylomicrons
• LDL
• HDL

Answer 3

LDL
-lipid transport from liver => other cells

HDL
-lipid transport from cells => liver

Chylomicrons
-lipid transport from gut => liver and other cells

Question 4

Lipid screening
What to do with specific results
-total cholesterol
-TAGs

Answer 4

Total cholesterol - 9+
-investigate for possible FHx of familial hypercholesterolemia even if no FHx of CVD

TAGs 20+
-refer to lipid clinic if not alcoholic or DM

TAGs 11-20
-repeat in a week

Question 5

How to interpret lipoprotein investigation results

• ApoA1
• ApoB
• ApoE
• Lp(a)

Answer 5

ApoA1 - approx HDL
ApoB - approx non HDL

ApoE genotype - hyperlipidemia risk
Lp(a) - increased familial risk

Question 6

Familial hypercholesterolemia

-when to investigate

Answer 6

LDL receptor/ApoB100 issue
Autosomal dominant
-homozygous more severe

Investigate if

• Total cholesterol 7.5+
• LCL 4.7+
• physical signs - tendon xanthomata, arcus
• CHD in younger age groups within family

1st line - statins or ezetimibe
2nd line - apheresis of lipid
3rd line - liver transplantation