lipoproteins and their disorders .

1. Sarah mutni almutairi .
College of Medicine
second year
CVS block

2. -Define dyslipoproteinemia
-Outline the different types of dyslipoproteinemia,
-Outline common causes of dyslipidemias
-List complications of dyslipoproteinemia

3. Introduction :

4. Lipoproteins:
Definition :
Lipoproteins are molecular complexes that consist of lipids with proteins.They are the
transport vehicle for lipid in the circulation. Lipoproteins deliver the lipid components to
various tissues for utilization and storage .
Function :
The major function of LPs is to transport TAG, Cholesterol and phospholipids around the
body.

5. Structure of
lipoproteins:
Outer coat:
-Apoproteins
-Phospholipids
-Cholesterol
Inner core:
-TG
-Cholesterol ester
Spherical molecules of lipids and proteins
(apoproteins)

6. Cont.
Protein part: Apoproteins or apolipoproteins
Abbreviations: Apo-A, B, C, D, E
Functions:
Structural and transport function
Enzymatic function
Ligands for receptors
Lipid part:
According to the type of lipoproteins
Different lipid components in various combinations

7. Classification of lipoproteins :
Atherogenic
Anti-
atherogenic

8. CONT..
1- CHYLOMICRONS :
Derived from intestinal absorption of triacylglycerol and other lipids.
2-VERY LOW DENSITY LIPOPROTEINS (VLDL) or pre β-lipoproteins :
Derived from the liver for the export of triacylglycerol .
3- LOW DENSITY LIPOPROTEINS (LDL) or β-lipoproteins :
Representing a final stage in the catabolism ofVLDL .
4-HIGH DENSITY LIPOPROTEINS (HDL) or α-lipoproteins :
Involved in cholesterol transport from peripheral tissue to the liver and also inVLDL
& chylomicron metabolism.
FOUR MAJOR GROUPS OF PLASMA LIPOPROTIEN :

10. -Atherosclerosis and hypertension.
-Coronary heart diseases.
-dyslipoproteinemias (hypo- and hyper-).
-Fatty liver.
Lipoproteins and their Related Clinical Problems :

11. 1-Define dyslipoproteinemia.
Inherited or acquired (secondary) defects in lipoprotein
metabolism lead to the primary condition of either
Hypo- or hyperlipoproteinemia .

12. 2-Outline the different types of dyslipoproteinemia.
1 2
Hypolipoproteinemia Hyperlipoproteinemia

13. 1-Hypolipoproteinemia :
DefectName
No chylomicrons ,VLDL , LDL are formed because
of defect in the loading of apo B with
Lipid .
Abetalipoproteinemia
All have low or near absence of HDL
Familial alpha-lipoprotein def.
Fish eye disease
Apo-A-I def.
Tangier disease.

14. 2-hyperlipoproteinemia (primary):‫مهم‬
DefectName
Hypertriacylglycerolemia due to def. of LPL ,
abnormal LPL or C-ll def. causing inactive LPL .
Familial lipoprotein lipase def.
Type l
Defective LDL receptor or mutation in ligand
region of apo B-100 .
Familial hypercholesterolemia
Type ll a
Def. in remnant clearance by the liver is due to
abnormality in apo E
Familial type lll hyperlipoproteinemia
Overproduction ofVLDL often associated with
glucose intolerance and hyperinsulinemia .
Familial hypertriacylglycerolemia
Type lV
Increase concentration of HDL .Familial hyperalphalipoproteinemia
Def. of the enzyme leads to accumulation of large
triacylglycerolrich HDL &VLDL remnants .
Hepatic lipase def.
Absence Of LCAT leads to block in reverse
cholesterol transport .
Familial (LCAT) def.
Apo a shows structural homologies to
plasminogen .
Familial lipoprotein (a) excess

16. Secondary causes of hyperlipidemia :

17. 3-Outline common causes of dyslipidemias
BUT FIRST , what dyslipidemia mean ?
An abnormal concentration of lipids or lipoprotei
n in the blood.

18. 3-Outline common causes of dyslipidemias
1-Primary causes:
Primary causes are single or multiple gene mutations that result in either
overproduction or defective clearance ofTG and LDL cholesterol, or in
underproduction or excessive clearance of HDL .

19. * DM :
1- ↓ insulin → ↑ lipolysis in adipose tissue → ↑ mobilization of FFA to liver → ↑acetyl COA → ↑ cholesterol.
2- ↑ FFA → ↑VLDL → ↑TAG .
* Liver disorder :
Chronic liver disease → liver can not catabolizes LDL →↑ LDL
* Thyroid diseases :
Hypothyroidism → ↑ level of LDL
Hyperthyroidism→ ↓ level of LDL
* Renal disorder :
Nephritic syndrome → ↑ LDL
* Cushing syndrome :
↑ glucocorticoid → ↑VLDL → converted to LDL → ↑TAG
2- Secondary causes : acquired disorders due to other diseases That affects
circulating levels of lipids in blood.

20. 4-List complications of dyslipoproteinemia .

21. Complication of hyperlipoproteinemia :
1- Xanthelasma site : (periorbital)
Due to sharply demarcated deposit of yellowish fat underneath the skin.
2- Atherosclerosis .
3- Corneal Arcus site : (around the iris of the eye)
Due to lipid infiltration of the corneal stroma.
4- tendon xanthomas site: (in extensor tendons of hands ,
feet ,Achilles tendon & patellar tendon )
Due to deposition of yellowish cholesterol-rich material in tendons.

22. Cont..
5- Eruptive xanthomas
site: (occur in crops , particularly over the buttocks )
Due to accumulation of lipids in large foam cells within the skin.
6- Lipemia retinalis:
characterized by the hyperlipidemic vascular lesions-whitish color of vessels,
lipid infiltration into the retina and decrease of visual acuity
7-Thrombosis : Stroke (cerebral )
Hyperlipidemia has been linked with increased stroke risk because plaque build up
due to hyperlipidemia can loosen and cause an ischemic stroke.The plaque lodges
in the brain and prevent blood from flowing to the brain, resulting in cell death. An
ischemic stroke is the most common type of stroke

23. Cont..
8-Coronary heart disease .
Premature CoronaryArtery Disease :
the vessels become so narrow that the blood cannot pump through to the
heart. Early symptoms are chest pain and difficulty breathing, and
eventually can cause a heart attack.

24. Complication of hypolipoproteinemia
1-Coronary atherosclerosis .
Due to decrease HDL lead to accumulation of cholesterol in the intima of large
artery.
2-Yellow (orange)tonsillitis (very rare)
Due to decrease HDL cholesterol ester are accumulated in tonsils
3-Recurrent peripheral neuropathies .
.accumulation of oxidized lipids in myelin, leading to peripheral neuropathy
4- Depressed tendon reflexes
Decrease in HDL cholesterol ester are accumulated inTENDON

25. Summary :
Dyslipoproteinemia : Inherited defects in lipoprotein metabolism
Types : 1-hypolipoproteinemia
2-hyperlipoprotinemia
Dyslipidemia :
An abnormal concentration of lipids or lipoprotein in the blood.
Causes : primary or secondary
The complication of dyslipoproteinemia

26. Any Questions ?

27. References :

28. Thank you