Atherosclerosis• Please read Robbins p 515-524

Arteriosclerosis- 3 types

• Atherosclerosis - intimal fibrous plaques with a central core rich in lipid• Monckeberg medial calcific sclerosis

- calcifications in media• Arteriolosclerosis - thickening of

media - hypertension and diabetes

Atheromatous Plaque

• 0.3 to 1.5cm, yellow• May coalesce• Cells - smooth muscle & macrophages• Connective tissue extra cellular matrix• Intracellular and extracellular lipid

deposits• Neovascularization

Typical atheroma

Pathogenesis

• Chronic endothelial injury• Insudation of lipoproteins• Adhesion of blood monocytes• Adhesion of platelets• Release of factors from activated platelets• Proliferation of smooth muscle cells• Enhanced accumulation of lipids

1)Chronic endothelial injury. 2)Insudation of lipoproteins. 3)Adhesion of blood monocytes4) Adhesion of platelets. 5) Release of factors from activated platelets. 6)Proliferation of smooth muscle cells. 7) Enhanced accumulation of lipids

Complicated lesion

• Calcification• Rupture or ulceration - discharge of

debris - micro embolus• Hemorrhage• Thrombosis• Weakening of wall, aneurysmal

dilation

19 y/o man killed in a auto crash-- early fatty streaks-- oil red O stain

Lower- 30 y/o fatty streaks & early atheroma, Upper 50 y/o

Early complex lesions

Severe atherosclerosis in a 70 y/o man many ulcerated complex plaques

Recent thrombus well developed plaque

Early intimal hyperplasia

Early intimal hyperplasia

Well developed plaque

Complicated plaquelipid corecalcification

Severe occlusion, coronary art. lumen

Cholesterol crystals calcification

lumen

Risk factors

• Non-modifiable• Increasing age• Male gender• Family history• Genetic abnormalities

Potentially Controllable

• Hyperlipidemia• Hypertension• Cigarette smoking• Diabetes

Lesser or Uncertain

• Obesity• Physical inactivity• Homocysteine• Postmenopausal estrogen deficiency• Alcohol• Lipoprotein (a)• Chlamydia pneumoniae

Other Factors

• Smooth muscle proliferation - oligoclonality • Infection• Viruses - herpesvirus + CMV in plaque• Chlamydia pneumoniae