Week 56: Atherosclerosis Flashcards
what is the framingham heart study and what factors risk factors does it cover?
large caucasian cohort study that predicts 10 year risk of angina, MI, death from CHD
age, sex, total cholestrol, HDL, smoking, diabetes, htn and fhx premature cvd
what is the inter-heart study and what are the 9 risk factors?
larger heart study with inc variation of participants
smoking, dm, htn, abdo obesity, psychosocial index, apoB-apoA1 ratio
protective: exercise, fruit/veg, alc
what does apo-B meausre?
LDL and non-HDL cholesterol good predictor of cvd
briefly explain dietary fat digestion
- fats emulsified in small intestine by bile salts from liver, and lipase/ colipase from pancreas (chyme in duodenum is major stim for release of pancreatic lipase and colipase)
- cholesterol esters go to cholesterol and FFA by enzymes
- micelles form and move into intest wall (mono and FFA move by simple diffusion)
- end products form chylomycrons, travel in lymph to body
what does lipoprotein lipase do?
sits on cap overlying adipose, skeletal muscle and other tissues to digest TG and deliver FA to tissues for immediate and stored energy
what is primary and secondary dyslipidemia?
genetic, LDL >4.5, tot chol >6.5, TG>3
unrelated to genetics, minor elevations of lipids
what are the five physical signs of genetic hyperlipidemia?
- tendon xanthomas
- palmer xanthomas
- eruptive xanthomas
- xantholasma
- corneal arcus
what are the five dyslipidemias?
- familial hypercholesteremia (most common, LDL-R does not bind apo-B properly- not a lot of receptor, not breaking down LDL)
- familial combined hyperlipidemia
- disbetalipoproteinemia
- lipoprotein lipase deficiency
- tangier dx (no HDL)
what would your blood work values need to be to start statin therapy?
ldl >2 or
apo-B >0.8 or
non-HDL >2.6
what do statins, PCSK9i, and ezetimibe do?
slow down liver production of cholesterol, inc removal of LDL from blood (to make bile)
block PCSK9 from breaking down LDL-R
blocks absorption of chol in small intestine
what are four things endothelial cells do in arteries?
- tight jxn to protect subendothelial space from blood borne elements
- maintain non thrombotic luminal surface
- maintain smc’s relaxed state (reg of flow sensitive to vasc tone)
- antioxidant properties (superoxide dismutase)
how to smc’s fxn normally?
modulate diam and tone of vessel, normally relaxed, low fxn for making ECM
how does ECM fxn normally in vessel?
structural integrity, strength and flexible components
what parts of vessels are more exposed to non-laminar blood flow more than others and what can occur in these locations when damaged from non-laminar flow?
bends/ branches in vasculature,
activation of pro-atherogenic gene expression cascades by endothel cells (inc stickiness for WBCs), dec NO, inc ET, apoptosis
what can happen if you have loss of endothelial alignment in vessel? (3 things)
- inc luminal adhesion
- changes in subendothelial matrix/ lipid retention
- inc dendritic cells/ uptake oxLDL
bonus: endothelial cells are also less resistant to platelet aggregation, so thrombins can form
What causes WBC to go into subendothelial space (and what is fancy name)
subendothelial chemokines,
diapedesis
what part of the arterial intima retains lipids?
proteoglycans
this promotes inc foam cell production (macrophages engorging lipids)
what happens to smc’s in athero?
inc contractile mediators, dec vasodilation, inc inflamm mediators, inc migration of smcs into subendo space, inc free radicals, excess ecm
how does thrombus form over plaque?
endo cells less resistant to platelet aggregation
disrupted plaque leaks out factors and contents into blood, which triggers clot formation