lipid required for the production of steroids, sex hormones, bile acids, and
cellular membranes
cholesterol
where does most cholesterol come from?
foods of animal origin
what organ metabolizes cholesterol into its free form?
liver
how is cholesterol transported in the body?
Transported in the bloodstream by lipoproteins
form of lipid in the blood stream
•Produced in liver using glycerol and other fatty acids as the building blocks
•Storage source for energy
•When high --> deposited in adipose tissues
Triglycerides
proteins in the blood
Main purpose is to transport cholesterol, triglycerides, and insoluble fats
Lipoproteins
carry triacylglycerol from intestines to liver, skeletal muscle, and to adipose tissue
Chylomicrons
transport triacylglycerol from liver to adipose tissue
Very low-density lipoproteins (VLDL)
intermediate between VLDL and LDL, not usually detectable in blood
Intermediate-density lipoproteins (IDL)
which lipoproteins can be tested for?
VLDL
LDL
HDL
which lipoprotein is not usually detectable in blood?
Intermediate-density lipoproteins (IDL)
carry cholesterol from the liver to cells of the body "bad cholesterol"
Low-density lipoproteins (LDL)
collects cholesterol from the body’s tissues and vascular endothelium and brings it
back to liver “good cholesterol”
High-density lipoproteins (HDL)
which is the "bad" cholesterol
LDL
which is the "good" cholesterol
HDL
what is the indication for lipid profile?
Determine risk of atherosclerosis and to monitor abnormalities if abnormalities
found
,what is included in a lipid profile? (8 things)
•Total cholesterol
•Triglycerides
•HDL
•LDL- calculated
•VLDL
•Cholesterol/HDL ratio
•Triglyceride/HDL ratio
•Non-HDL-C
how do you order/obtain a lipid profile?
red top tube
+/- fasting (usually fasting bc eating affects triglycerides)
what is cholesterol usually bound to?
LDL > HDL
what is the target/normal cholesterol level?
<200 mg/dL
what can affect cholesterol levels?
variation from day-to-day
positional changes
how does position affect cholesterol levels? why does this matter?
15% less in recumbent position
will be lower in hospitalized patients
what are the interfering factors of cholesterol?
DRUGS
increase (ACTH, steroids, epinephrine, OCP, phenytoin, thiazide diuretics, vit D)
decrease (statins, niacin, nitrates, allopurinol)
what gender has higher normal HDL levels
females (>55)
what relationship does HDL have with risk of CAD
inverse
the lower the HDL the higher the risk of heart disease
what are the five subclasses of HDL
2a, 2b, 3a, 3b, 3c
which subclass of HDL is cardioprotective
ONLY 2B
when HDL >60 then 2B predominates
what is the use of total cholesterol/HDL ratio
more accurate than HDL at predicting the risk of CAD
what is the ideal total cholesterol/HDL ratio
3:1
must be at least 5:1
high levels of LDL means risk of what?
, atherosclerosis
what is target LDL based on
risk factors for atherosclerosis
how do you calculate LDL
Friedwald formula
•LDL = Total cholesterol - (HDL + [Triglycerides ÷ 5])
when would LDL be inaccurate? what do you do to fix this?
if triglycerides > 400 mg/dL
order lipid profile fasting!!!
in what endocrine condition is LDL and VLDL decreased in?
hyperthyroidism
in what endocrine condition is LDL and VLDL increased in?
hypothyroidism
how can LDL be classified
particle size - 7 classes
what are the most commonly elevated forms of LDL?
what does this mean?
IIIa and IIIb
•Small enough to get between endothelial cells and cause atherosclerosis
which forms of LDL are associated with very aggressive arterial plaques?
IVa and IVb
what is the predominate carrier of triglycerides but also carries some cholesterol?
VLDL
what is the critical value of triglycerides
>400mg/dL
are normal triglyceride values affected by gender?
yes!!
females (35-135) are usually lower than men (40-160)
what interferes with triglyceride levels?
Ingestion of fatty meals and alcohol = elevated
Drugs can increase (OCP, estrogen) or decrease (statins, ascorbic acid) them
triglycerides are mostly carried by what? can also be carried by what?
mostly carried by VLDL but can also be carried by LDL
what causes decreased triglycerides?
•Malabsorption syndrome
•Malnutrition
•Hyperthyroidism
what are the types of troponin
•Cardiac-specific troponin T (cTnT)
•Cardiac-specific troponin I (cTnl)
what do high sensitivity troponins do?