Low Density Lipoproteins & High Density Lipoproteins

7/28/2019 Low Density Lipoproteins & High Density Lipoproteins

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LOW DENSITY LIPOPROTEINS &

HIGH DENSITY LIPOPROTEINSHDLs

Triglyceride from unsaturated fats combine withcholesterol and proteins form HDL

Transport cholesterol from the body tissues to theliver

Have greater proportion of proteins

Reducing the depositing of cholesterol Exercise tends to increase HDL

Smoking reduces HDL

HDL help to remove cholesterol from the plaque


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LDLs Triglycerides from saturated fats combine with

cholesterol and proteins form LDLs

Major cholesterol carriers in the blood

Have lower proportion of proteins Increases the formation of fatty plaques of

atherosclerosis

Excess LDLs overload membrane receptors Receptors help to remove LDL from the blood

Saturated fats also interfere with LDL receptors

and elevates the risk of atheroma formation


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Apolipoproteins

Protein components of lipoproteins

Formed in the liver and intestine

Stabilizing the structure of lipoproteins andrecognizing receptors involved in lipoprotein

uptake

Different forms of apolipoproteins are ApoA,Apo B and Apo E


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Apo A- Major protein in HDLHelps to remove cholesterol from blood tothe liver

Apo B- Major protein in LDLTransfers cholesterol from the blood tocells

Apo E- Major component of HDLs and VLDLsInvolved in the removal of excess

cholesterol from the blood to the liverIt has three alleles producing three forms of proteins-E2,E3 and E4

E4 slows the removal of cholesterol from the blood


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Cholesterol & CVDs

High level of LDLs in the blood increases the

risk of CVDs

High level of HDLs in the blood decreases the

risk of CVDs


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Positive and negative correlation

Correlation-A change in one variable is reflected bya change in another variable

Causation-A change in one variable is responsiblefor a change in another variable

Positive correlation-Increase in one variableincreases another variable

Negative correlation-Increase in one variabledecreases another variable


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Cholesterol and CVD


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There is a positive correlation between

the level of LDL concentration in bloodand risk of CVD-As LDL level increases

risk of CVD also increases

A negative correlation between HDLconcentration in blood and risk of CVD


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Framingham Heart study


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Study to find out relation of HDL and LDL

in coronary artery disease

The study involved 5209 men and womenbetween the ages of 30 and 62 from the

town of Framingham, Massachusetts


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The result of the study indicates,

The lower the HDL-C level,the greater is therisk of developing CAD

The higher LDL-C level,the greater is the risk

of developing CAD

The risk nearly reaches three fold when LDL-

C is 220 mg/dl and HDL-C is 25 mg/dl

HDL-C remains an important risk factor even

in patient with a low LDL-C level


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Prospective Cardiovascular Munster

study

Confirms Framingham data

It showed that the incidents of CHD decreasedwith increasing high density lipoprotein

cholesterol

Study includes 4407 Germen men aged

between 40 to 65 followed for 6 years


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There is a clear link

between LDL/HDL ratioand death from CHD

A LDL/HDL ratio above 4.0drastically increases therisk of death from CVD

Low Density Lipoproteins & High Density Lipoproteins

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