Lecture 8: Atherosclerosis & CHD Flashcards
What are the layers of an artery?
- Tunica Intima: Elastic
- Endothelium: Inner lining of the tunica intima and the Thromboresistant layer
- Tunica Media: Smooth
- Tunica Externa/Adventitia
Define atherosclerosis.
- Athero = soft, lipid-rich material in the center of atheroma.
- Sclerosis = scarring, referring to the connective tissue in a plaque.
- A pathological process that results in coronary, cerebral and peripheral artery disease.
What are the first signs of atherosclerosis?
Fatty streaks within the arterial walls.
What are the 6 histologic steps to atherosclerosis development?
- Fatty streak formation
- Fibrous cap formation
- Disruption of the vasa vasorum
- Proliferation of the fibrous plaque
- Development of an advanced lesion
- Intraplaque hemorrhage
What makes fatty streaks?
Accumulation of foam cells and ECM, leading to lipid accumulation.
Specifically biglycan is the protein that traps LDL and VLDL in coronary arteries.
The foam cells can also trap T lymphocytes.
Why does a fibrous cap develop?
- If a plaque appears and remains stable.
- It will wall it off with a collagen tissue layer.
Makes the plaque even more stable ):
How is the vasa vasorum disrupted by a plaque?
- Expansion of plaque
- Rupture of plaque vasculature, extending to the arterial wall.
- Microvascular hemorrhage and occur and neovascularization will occur.
Why does proliferation of the fibrous plaque occur?
Accumulation of connective tissue
What characterizes an advanced lesion?
- Necrotic, lipid-rich core.
- Calcified regions
What is positive remodeling?
Increased vessel size in early CHD to compensate for loss of lumen. (Leads to unstable angina)
What is negative remodeling?
Vessel shrinks due to obstructive plaques, leading to stable angina.
What is the critical event in atherosclerosis?
- Intraplaque hemorrhage due to plaque neovascularization.
- The plaque will rupture and lead to ischemic events.
What factors contribute to the pathogenesis of atherosclerosis?
- Endothelial dysfunction
- Inflammatory & Immunologic factors
- Plaque rupture or erosion
- Risk factors for development of disease
What is the primary underlying etiology of endothelial vasodilation dysfunction?
Errors in nitric oxide, which is precipitated by oxidized LDL.
How can we improve endothelial vasodilator dysfuction?
- Correct HLD via diet/statins
- ACEi if HTN present
- (ehhhh) High dose of antioxidants (Vit C, flavonoids)