1. Aging of the Cardiovascular System (continued)
Chapter 16
P.S. Timiras

2. Total or partial occlusion of coronary artery due to plaque rupture and thrombosis can cause angina or frank myocardial infarction.
Plaques likely to rupture termed unstable. Rupture usually occurs in lipid-rich and foam cell-rich peripheral margins and may result in thrombosis and arterial occlusion.

3. Table 16-5: General Characteristics of Atherosclerotic Lesions
Early onset -- progressive
Focal lesions
Early lesions
Advance lesions
Damage, Repair, Regression
Progression of localized lesions influenced by:
Local factors: vessel structure and metabolism, blood turbulence
Systemic factors: diabetes, hypertension, stress, genetic predisposition

4. Table 16-4: Localized Factors Contributing to Atherosclerosis
Marginal vascularization of arterial wall
Relative ischemia
Limited metabolic exchange
Blood turbulence and mechanical stress

5. Endothelium-derived relaxing factor (EDRF)/nitric oxide (NO) induce vasal dilation
Endothelins induce vasal constriction
Vascular endothelial growth factor (VEGF) induces mitogenesis and promotes angiogenesis and wound healing
Cytokines participate in repair of vascular wall; promote cell adhesion and stimulate thrombotic activity

6. Significance of Age Changes in the Vascular Endothelium
Significance of Age Changes in the Vascular Endothelium *Table 16-2, page 293*
Endothelial cells line the internal wall (intima) of the blood vessels.
While the muscle cells and the elastic fibers in the vascular wall regulate blood vessel motility (contraction and relaxation), the endothelial cells, serve as protective lining against trauma, infections, etc,
Endothelial cells undergo significant changes with aging indicative of abnormal function.
These alterations by themselves may induce pathology or may predispose with other factors to atherosclerosis

7. Significance of Age Changes in the Vascular Endothelium
Significance of Age Changes in the Vascular Endothelium *Table 16-2, page 293*
Endothelial cells undergo significant changes indicative of abnormal function
The imbalance of vascular tone is manifested by increased vasoconstriction
Endothelins EDRF, NO
Vascular integrity (cell proliferation and migration, wall remodeling) and injury repair through local growth factors are impaired
VEGF Cytokines
Maintenance of blood fluidity is disrupted with increased cell adherence, blood coagulation, and thrombogenic properties
Cytokines
These alterations by themselves may induce pathology or may predispose with other factors to atherosclerosis

9. Table 16-8: Theories of Atherosclerosis
Lipid accumulation
Myoclonal
Thrombogenic
Inflammation
Free Radicals
**See page 299**

11. Regulation of coronary blood flow:
Vasodilation
O CO2
Vagal Stimulation
Vasoconstriction
Angiotension II
Sympathetic stimulation

12. High homocysteinemia and Protein C