This document discusses lipoproteins and lipid profiles. It describes the different types of lipoproteins including HDL, LDL, VLDL, and chylomicrons. HDL is described as "good cholesterol" that removes cholesterol from the body, while LDL is described as "bad cholesterol" that deposits cholesterol in tissues and increases disease risk. Normal ranges for HDL and LDL are provided. Factors that influence lipid profiles like smoking, alcohol, medications, and medical conditions are also summarized.

1. Lipid profile
HDL , LDL
(5TH stage)

2. Lipoprotein are proteins in blood whose main purpose is to
transport cholesterol , triglycerides and other insoluble fats. With
the use of electrophoresis these lipoprotein can be grouped into :
1- Chylomicrons (origin)
2- LDL ( beta- lipoproteins)
3- VLDL (prebeta- lipoproteins )
4- HDL (alpha-lipoproteins)
2- Ultracentrifuge
3- enzymatic kit

3. • High Density Lipoprotein(HDL) are carries of cholesterol , that
are produced in the liver .
• The main function of HDL is to remove cholesterol for excretion.
Also HDLs prevent cellular uptake of cholesterol and lipids. These
potential actions may be the cause of their protective
cardiovascular characteristics associated with HDLs(good
cholesterol) within the blood.
HDL :
Male > 0.75 mmol/l OR > 45mg/dl
Female > 0.91 mmol/l OR > 55mg/dl

4. Low density lipoproteins(LDL) are cholesterol rich.
Cholesterol carried by LDLs can be deposited in the peripheral
tissue and is associated with increased risk of arteriosclerotic and
vascular diseases. Therefore , high level of LDLs ( bad cholesterol
) are atherogenic.
LDL (mg/dl) = Total Cholesterol – (HDL + TG/5)…….Friedwald
Formula
• LDL : > 3.3 mmol/l or 60-180 mg/dl

5. Interferingfactors
• Smoking and alcohol ingestion decrease HDL
• HDLare age and sex dependent
• Oralestrogen therapy show increase HDL anddecrease LDL
While in pregnancy LDL increased
• Steroid , diuretics, beta- blocker decreased HDL levels
• HDLlevel is elevated in hypothyroidism and diminished in hyperthyroidism.
• Specimen
Collect 5- 10 ml venous blood
1-Patient should fast for 12-14hr
2-No alcohol should be consumed for at least 24 hr
3- If possible, stop all medication for at least 24 hr

6. Increase level of HDL
• Familial lipoproteinemia
• Excessive exercise
Decrease level of HDL
• Familial low HDL
• Hepatocellular disease
(hepatitis or cirrhosis)
• Hypoproteinemia ( nephrotic
syndrome or malnutrition)
mutation in enzyme responsibal for
formation lipid ,apo protine 1

7. Estimationof HDL-cholesterol
• Principle
The chylomicrons, VLDL and LDL that are contained in the
sample are precipitated by addition of phosphotungesticacid in the
presence of Mg. the supernatant obtained after centrifugation
contains HDL from which the cholesterol can be determined by
using the cholesterol enzymatic kit.

8. Procedure
R1 : phosphotungestic acid and magnesium chloride.
R2 : standard
• Mix 200 µl of sample and 400 µl of R1 , stand 10 min at room
temperature , centrifuge at 5000 rpm for 10 min, collect the
supernatant and proceed it as a sample in the total cholesterol.
•

9. • Cigartic smoking effect on LCAT activity and altering the cholesterol
ester transfer protein(CETP)(which exchange cholesterol ester from
HDL2 to VLDL leading to decrease in HDL synthesis .in addition
smoking cause oxidative stress which effect on HDL (become
dysfunction and loss atheroprotection properties)
• Estrogen increase in apo A1 production ( rate of synthesis in
liver)leading to increase in HDL synthesis
• Hyperthyroidism lower HDL because thyroid hormone effect on the
activity of CETP
• Exercise decrease the activity of CETP (increase HDL synthesis) and
increase the activity of LCAT (increase function of HDL)