Flashcards in LMP301 Lecture 6: Lipids & Cardiac Disease Deck (88)
Ischemic heart disease
Inadequate supply of blood to the heart; some kind of blockage causes heart to stop working.
Ischemic heart disease
____ of deaths from IHD can be prevented
Differences between men and women in terms of IHD
Symptoms in women are less characteristic than men -> under diagnosis
Risk for men and women are the same
Disease that may result from fat deposits in the arteries
2. Cerebrovascular disease
3. Peripheral vascular disease
Peripheral vascular disease
Blood can't flow the the extremeties
Where is the lipid core found?
Nested in the intima
What holds the lipid core in place?
4 types of lipids
Which lipids are used for fule?
TG and FA
Which lipids can be found in the membrane?
Cholesterol & phospholipids
Functions of cholesterol
Production of hormones
Functions of phospholipids
Make up cell membranes
Transporter for lipids
Lipoproteins carry circulating lipids in plasma & lympth
Carriers for FFA
Exogenous pathway for lipids
Lipids consumed from fats
Endogenous pathway for lipids
Lipids made by the body
Outline exogenous pathway for lipid metabolism
Dietary fats transported in body by chylomicrons (used in muscle or stored in adipose). Remnant returns to liver to be metabolized. Liver secretes bile which help emulsify fats in the intestines.
Outine endogenous pathway of lipid metabolism
Liver produces VLDL -> broken down into TG and IDL. TG goes to muscles and adipose tissue while IDL can return to liver or become LDL. LDL deposits cholesterol in extra-hepatic cells, then return to liver.
Liver can also make HDL which picks up extra cholesterol from cells-> return to liver to be metabolized.
Liver produce bile from the cholesterol which is used in the exogenous pathway
Cells other than liver cells
What does HDL do?
Reverse cholesterol transport
Reverse cholesterol transport
Take extra cholesterol from cells and returns to liver (prevent buildup)
List the lipoproteins in order of least dense -> most
Which is the largest lipoprotein?
Purpose of CM
Transport TG and TC
What happens to the CM remnant?
Metabolized by the liver to give VLDL
Purpose of VLDL
Carry mostly TG and some TC to adipose & muscle tissues
What happens to VLDL during transfer?
Some of it's surface components are lost
Purpose of IDL
1. Return to liver
2. Become LDL
Purpose of LDL
Carries TC to peripheral tissues
What do LDL bind to?
Specialized receptors on liver & peripheral cells
Promote formation of fatty plaques in the arteries
Which LP is atherogenic?
Statins try to lower...
HDL is composed of
proteins & phospholipids
Where is HDL made?
What happens to HDL during transport?
Accepts TC from other lipoproteins; increase in size (HDL-1 -> HDL-2 -> HDL-3)
Purpose of HDL
Carries TC from peripheral tissues to liver (for removal) using reverse cholesterol transport
What is the only organ that can excrete significant amounts of cholesterol?
How does the liver excrete cholesterol?
Importance of bile salts?
Absorbs fat-soluble vitamins in the intestine
2 types of lipid disease
1. Inherited (genetic factors)
2. Acquired (risk factors)
High levels of cholesterol
Genetic mutations that cause high levels of triglycerides
2 types of inherited lipid disease
2. Familial hypertriglyceridemia
Combination of 1 and 2.
Causes of FHC
Defect in LDL receptor: LDL is unable to return to liver, so excess amount circulates in the blood
Risk for those w/ heterozygous FHC gene
have MI in their 30's
Risk for those homozygous for FHC gene
have MI in childhood (1:1000000)
Marker for FHC
Build-up of fatty deposits in soft tissues (e.g. eyelids)
When the fibrous cap breaks and ruptures the artery, blood clot that forms at the site of damage will clog the artery
How to treat MI and stroke surgically?
1. Enzymes that break the clot
2. Balloons to open up the vessel
Pathogenesis of IHD
1. Oxidant status
2. Inflammatory response markers
LDL in lipid plaque become oxidized by free radicals.
Marker for oxidant status
Homocysteine in some patients (reducing AA)
Inflammatory response markers
Tissue damage at atheroma triggers inflammatory response.
Oxidation of LDL also triggers inflammatory response
Marker for inflammatory response?
Acute phase reactant (appears quickly) when body has an inflammation.
Used to identify those at higher risk for IHD.
Role of Lp(a) in IHD
Interfere with plasminogen process.
Plasminogen is anti-clotting factor, so Lp(a) causes clotting to happen.
How to prevent IHD?
1. Routine screening of cholesterol after the age of 40
2. If screen shows problems: fasting lipid profile
LDL + HDL + VLDL
TG / 2.2 (MUST BE FASTING)
TC - (HDL + TC/2.2)
Which lipoprotein is usually calculated? What conditions must be met?
TG must be less than 4.5 mmol/L
Lipid indicators of risk for IHD
1. TC : HDL ratio
Apo-B is a marker for...
Apo-B might be more useful in patients with...
Apo-A1 is a marker for...
Benefit of measuring Apo-B and A1 over lipid profile
NO need to fast
Problems with cholesterol screening
1. Cholesterol in IHD patients and non-IHD patients may be the same
2. HDL is not accounted for
3. Variability in cholesterol measurement (up to 12%)
4. Other risk factors
5. Low cholesterol diets hard to follow
6. Research for cholesterol <-> IHD outdated
7. Cost high
Framingham heart study
Model for 10-year risk of coronary artery disease (guildline for heart disease risk factors).
ATP-III is the treatment guidelines developed.
What automatically puts you at high risk for IHD?
Risk factors associated with IHD from the Framingham heart study
10-year risk score
Points that = some level of risk for developing CVD in the next 10 years
Risk categories from the 10-year risk score
High, moderate, low
Metabolic syndrome (X)
A cluster of risk factors that are associated with heart disease & diabetes.
Getting 3 or more of those factors = metabolic syndrome
Key metabolic changes (metabolic syndrome)
1. Impaired fasting glucose (Insulin-resistance)
2. Abdominal fat (small-dense LDL)
management of IHD
1. TLC: therapeutic lifestyle changes
3. CABG: coronary artery bypass graft
2 TLC changes to manage IHD
2. Vegetarian diet
Vein grafted: replace coronary artery
Acute Myocardial infarction
Symptom for AMI
crushing chest pain down left arm and jaw
Anti-thrombolytic therapy usually uses
streptokinase: enzyme that dissolves blood clots or TPA