Hyperlipidemia Flashcards
what blood does arteries carry
oxygenated
what blood does veins carry
deoxygenated
what is hyperlipidaemia
increased fat molecules in the blood - tryglyceride and cholestrol
initial phase of atherosclerosis
asymptomatic
what is primary hyperlipidaemia
Mainly due to genetic deficiency
what is secondary hyperlipidaemia
caused due to lifestyle and other metabolic diseases
what is secondary hyperlipidaemia
caused due to lifestyle and other metabolic diseases
what is hypercholesteroaemia
increased levels of cholesterol
what is hypertriglycerideaemia
increased level of tryglyceride
what is lipoproteins
proteins and lipids
what is the role of lipoproteins
transports vehicles for tricylglycerol and cholesterol around the body
how many broad categories are there of lipoproteins
5
what are the 5 broad categories of lipoprotein and what do they do
-chylomicrons - transport exogenous TAG and cholesterol from intestine to tissues
-VLDL
-IDL
-LDL
VDL + iDL + LDL - transport endogenous TAG cholesterol from liver to tissues
-HDL - transport endogenous cholesterol from tissues to liver to be matabolised
chylomicron is the largest and it goes down in size
What is the structure of lipoprotein
- non polar core - trigyaclglycerol and cholestrol esters
- amphophilic surface (polar) - apoproteins , phospholipids and cholesterol
what is the function of lipoproteins
- when you consume food there is different types of lipids
- large fat droplets would be formed
- bile salt from liver coat fat droplets
- pancreatic lipase and colipase break down fat into monoglycerides and fatty acids stored in micelles
- monoglyceride and fatty acid stored in micelles move out and enter cells by diffusion
- cholesterol is transported into the cell
- absorbed fat combine with cholesterol and proteins in the interstital cell to form chylomicron
- cholesterol, triglyceride and protein is packaged in the smooth er
- chylomicrons are removed by lymphatic system
Function of lipoprotein:
what happens after chylomicron is in the blood stream
- This is when the chylomicron is in the bloodstream
- This will supply all the fatty acids and cholesterol to the target tissues
- The excess will be stored - adipose cells
- The remnant chylomicron go to the liver to be metabolised
- The liver will produce endogenous tag and cholesterol
- It will be packaged into very low density lipoproteins
- These lipoproteins will start to supply fatty acid molecules which is are similar to chylomicron
- Release the fatty acids for muscles and other tissues
- Excess will go to adipose cells for storage
- By supplying this it will become smaller in size which will make them intermediate density lipoprotein and then LDL lipoprotein
- LDL will go to the target tissue and supply all the cholesterol using the LDL receptor and endocytosis mechanism
- Excess amount of cholestrol will be stored in the plasma membrane or in small patches called aveoli and this is when the HDL will come over
- The HDL will come and pickup the excess amount of cholesterol from the cell membrane and use different mechanisms such as direct and indirect mechanisms through LDL or VLDL and supply all the cholesterol to the liver to get it metabolised
- Liver will produce bile cells and other materials and sone cholesterol will be recycled aswell
- These are the mechanisms how the lipoproteins are transporting exogenous tag and cholesterol to the body tissues
- Endogenous tag and cholesterol to the body tissues
- HDL is collecting excessive amount of cholesterol from the tissues and take it to the liver to get it metabolised
what are the causes of hyperlipideamia
-nutrition, genetics, medication
-genetic - lack of ldl receptors, mutations in LDL
-primary hypercholestrolaemia - genetic causes, deficiency or defect in LDL receptors
-Secondary hypercholesterolemia:- Lifestyle , taking calories and inactivity
Metabolic disorders - diabetics, cholestrol
Hypertriglyceridemia - excessive amount of tag is developed
what are the diagnosis of hyperlipideamia
- no obvious symptoms
- blood tests should be done in fasting conditions
- should be tested regularly after the age of 40, with fam history of SVD, diabetics, obesity, hypertension
what are the normal ranges
what are non medical treatment of hyperlipideamia?
- healthy balanced diet - replace saturated fat with fruit and veg - reduce animal fat
- take omega-3 FAs regularly
- regular excerise - weight loss
- avoid smoking and drinking
what medications can be taken for hyperlipideamia
Statins: Inhibit cholesterol biosynthesis (HMG-CoA reductase)
Different types: atorvastatin, simvastatin and rosuvastatin
Should be prescribed only to people at high risk for CVDs
Taken for life long as it can reverse the cholesterol if stopped
Aspirin: Anti-platelet drug that inhibits platelet activation
Should be prescribed with a low dose for people at high risk
Periodic blood test is required to check the liver functions
Ezetimibe: Blocks the absorption of cholesterol from food and bile
Reduced side effects compared to statins
Can be taken on its own when statins can’t be prescribed
Taken as a combination with statins if the level is not reduced
Bile acid sequestrants: Binds to bile acid in small intestine and thus increase release of from the liver and reduce cholesterol
Bile acid sequestrants available in the UK include: colesevelam (tablets), colestyramine (resin), colestipol (resin)
May interefere with the absorption of lipid soluble nutrients
Fibrates: PPARα agonists that induce hepatic uptake and oxidation of cholesterol & TAG, and adipogenesis
bezafibrate, ciprofibrate, fenofibrate, gemfibrozil
Can be given when patients cannot take statins
Nicotinic acid or niacin or vitamin B3: Inhibits lipolysis in adipocytes and reduce lipid synthesis in the liver
Usually high concentrations are required
Associated with several side effects such as vasodilation, skin rash, hepatotoxicity and hyperglycaemia
lipoproteins from the intestine is secreted where?
lymph
Apo: b48
lipoproteins from the liver is secreted where
plasma
Apo-b-100
