Atherosclerosis pathology mbbs

pathology

1. ATHEROSCLEROSIS Dr. Ujwala M. Prof. Pathology

2. RISK FACTORS FOR ATHEROSCLEROSIS

3. ATHEROGENIC HYPOTHESES Insudation hypothesis Encrustation hypothesis Reaction to injury hypothesis Monoclonal hypothesis Intimal cell mass and neointima formation hypothesis Hemodynamic hypothesis

4. UNIFYING HYPOTHESIS

5. ROLE OF OXIDIZED LDL IN ATHEROGENESIS Readily ingested by macrophages Chemotactic for circulating monocytes Increases monocyte adhesion Inhibits motility of macrophages Favours recruitment and retention of macrophages Stimulates release of growth factors and cytokines Cytotoxic to endothelial and smooth muscle cells immunogenic

6. ROLE OF MACROPHAGE IN ATHEROGENESIS MACROPHAGE IL-1 , TNF , and MCP-1 Increases adhesion of leukocytes Toxic oxygen species Oxidation of LDL Growth stimulators & inhibitors Modulate the proliferation of SMCs Deposition of ECM protiens

7. ROLE OF ENDOTHELIAL CELL IN ATHEROGENESIS Increase in the permiability of the wall to lipoprotiens Acceleration of lipoprotien accumulation Permit platelet interaction with the vessel wall Subsequent release of growth factors Allow the formation of thrombus on the surface Neovascularization in the shoulders of fibrous caps

8. PDGF NO bFGF PGI2 IL-1 IGF-1 TGF ox LDL Endothelial cell Antigens PDGF EGF TGF α TGF β TxA2 IGF-1 PLASMA Angiotensin LDL

9. FATTY STREAK ATHEROMATOUS PLAQUE FIBROUS FIBROFATTY LIPID FIBROLIPID PLAQUES COMPLICATED PLAQUE

10. FATTY STREAK Fatty streaks are the earliest lesions of Atherosclerosis Fatty streaks are flat or slightly elevated lesions Contain accumulations of intracellular and extracellular lipid in the intima Found in young children as well as adults Cells filled with lipid droplets ( foam cells ) Mostly macrophages and few smooth muscle cells also contain fat droplets

11. Do not correspond to the distribution of athero- sclerotic lesions in adults Fatty spots are common in thoracic aorta but atherosclerosis commom in abdominal aorta Fatty infiltration represents the initial lesions of atherosclerosis Atherosclerosis - clinically significant lesions Fatty streaks are not significant clinically

12. COMPLICATED ATHEROSCLEROSIS CALCIFICATION ULCERATION FOCAL RUPTURE ( Atheroemboli ) HEMORRHAGE SUPERIMPOSED THROMBOSIS ANEURYSMAL DILATION

13. COMPLICATIONS Acute occlusion Chronic narrowing of vessel lumen Aneurysm formation Embolism