Athersclerosis Flashcards
What is ATHEROSCLEROSIS?
Chronic inflammatory disease of the inner layer (tunica intima) of arteries causing narrowing and hardening of the arteries
What is the cause of ATHEROSCLEROSIS?
Due to the accumulation lipid garbage (atheroma) followed by fibrosis
In which arteries does Atherosclerosis occur?
Medium (muscular) arteries (especially coronary and cerebral) and large elastic arteries (aorta) and it favors branch points
WHAT are some of the causative agents that cause the initial injury to endothelial cells that begin the ATHEROSCLEROTIC pathogenesis?
- Hemodynamic stress
- Carbon Monoxide
- Hyperglycemia
- Hypercholesterolemia
- Chlamydia
- Cytomegalovirus
What does the first step of ATHEROSCLEROSIS involve?
Injury to the endothelial cells cause impairment to the permeability barrier, the release of inflammatory cytokines, increased adhesion of monocytes, decreased secretion of vaso dilators nitric oxide and prostacyclin, and decreased release of antithrombotic substances
What is the second step of the Atherosclerotic pathogenesis?
Accumulation of LDL in the Tunica intima
How does the LDL get trapped in the intima?
By binding to extracellular matrix proteoglycans whose production is increased in hypertension
What happens to the LDL once trapped in the Intima?
Modified by Oxidation, glycation, and other processes
What is the role of the modified LDL?
Promotes leukocyte recruitment and foam cell formation (steps 3 & 4)
Why do Macrphages become overstuffed with LDL
Because they take up LDL via scavenger receptors which lack the feedback mechanism of LDL receptors
What is step 3 of the ATHEROSCLEROTIC process?
Leukocyte recruitment into the tunica intima
What molecules mediate the recruitment of Leukocytes into the intima?
Endothelial expression of Leukocyte adhesion molecules LAM, monocyte chemotactic protein 1, interferon inducible protein 10 and IL8
Besides leukocyte recruitment whatelse happens in step 3?
Recruitment of smooth muscle cells into the intima
What molecules mediate the recruitment of SMOOTH muscle cells into the intima?
- PDGF,
- TNF-alpha
- TGF-beta
- IL-1
Where do smooth muscle cells normally reside?
The Tunica media