Atherosclerosis, HDL and LDL Flashcards
What is the normal use of Cholesterol in the body?
- synthesis and repair of cell membranes and organelles
- precursor to steroid hormones
What is the normal use of Triglycerides in the body?
fuel source for muscle use and adipose tissue storage
What protein is critical for the metabolism of lipoproteins?
Apoprotein
VLDL is mostly composed of what?
Triglycerides
Chylomicrons are mostly composed of what?
triglycerides
what does exogenous lipid metabolism mean?
metabolism of fat which is from dietary intake. as opposed to endogenous lipid metabolism which takes care of fat produced from your liver.
Describe exogenous fat ingestion.
dietary fat is ingested–>in the intestine it becomes a chylomicron–>LPL takes the triglycerides out of chylomicron and uses them for storage or skeletal muscle etc.
–>After TGs are gone chylomicron is now chylomicron remnant–> remnant binds to remnant receptor on liver for further metabolism.
Describe exogenous metabolism.
liver produces VLDL–> LPL take TGs out of VLDL to use in body–> with TGs removed VLDL becomes IDL–>LPL converts IDL to LDL–> LDL binds LDL receptor on liver.
What is the role of PCSK9?
it prevents the LDL receptor from arising on liver and thus slows down lipid metabolism. There is a drug to inhibit PCSK9.
A patient who is fasting should have no circulating _______.
chylomicrons
Why is HDL beneficial in lipid metabolism?
can clear cholesterol out of the system by a route other than liver receptors.
what is the key elevated factor that leads to atherosclerosis (and coronary heart disease risk)?
LDL-C
Describe the pathophys of atherosclerosis.
circulating LDL is taken up into the subendothelial space. Gets oxidized there (this is one reason why anti-oxidants are a good thing). It releases pro-inflammatory cytokines. Monocytes go in there next and eat the LDL. These monocytes (macrophages) now turn into foam cells because they ate tons of fat. Foam cells and T-cells within the plaque cause MMP secretion and activation of tissue factors. Eventually you get accumulation of these cells which can turn into an atheroma. An atheroma in the subendothelial space is what can eventually rupture (if unstable) and lead to vessel thrombosis.
Whats the difference between minimal, moderate, and severe atherosclerosis?
in minimal and moderate we see compensatory expansion of the blood vessel to keep lumen the right size. In severe, the compensatory mechanism is overcome and the lumen narrows.
Whats the difference between a vulnerable and a stable plaque? How do you stabilize a plaque?
a vulnerable plaque has a thin fibrous cap and is subject to rupture.
Lower cholesterol.
What are the different atherogenic lipoproteins? Why are these important.
LDL, VLDL, IDL, remnants.
They are central to the initiation and progression of atherosclerosis
Adults ____ y/o and older should have a lipid panel done every 5 years.
20.
the process of cholesterol leading to atherosclerosis happens fast and at any age.
false. it is a slow progressive process that likely starts at a young age.
How do risk factors in a patient correlate with LDL-C goals? what are the specific numbers?
1 RF– goal LDL-C level
what is the formula to determine lipoprotein levels.
LDL=total cholesterol- HDL - (TG/5)
This might not be that important but its a good way to think about it.
note: TG/5 only works when TGs
What are the four major Statin benefit groups?
- individuals with known clinical ASCVD
- individuals with LDL >/=190
- individuals with diabetes
- individuals without diabetes but who have an estimated 10-year ASCVD risk >/= 7.5%
How does calcium relate to risk for ASCVD?
elevated coronary calcium suggests elevated risk of atherosclerosis
Severe hypertriglyceridemia is probably a risk factor for ASCVD, right? So we should probably lower them right?
welllllll, it is a risk factor for ASCVD but its unclear if lowering it actually helps.
its also a risk factor for acute pancreatitis
A low HDL _____ your risk for CV disease regardless of LDL levels.
increases.
However, we’re not sure if raising HDL-C actually helps, just like not sure if lowering TGs actually helps.
Men or women are at higher risk for CVD?
men… until over 80, then more women are at risk (probably because the men that should be in this category are dead by then).
CVD is the leading cause of death in our society. At what age group is it the most serious?
under 85 CVD=cancer in deaths. Over 85 CVD is the leading cause of death.
