Accumulation of lipoproteins in atherosclerosis in the form of
(Oxidised LDL) (499-Robbins-Pathologic basis of disease 8th)Accumulation of lipoproteins mainly LDL and its oxidized forms in the vessel wall OXIDIZED-LDL1. In ingested by macrophages through scavenger receptors distinct from the LDL receptor thus forming foam cells2. Increases monocytes accumulation in lesions3. Stimulates release of growth factors and cytokines4. Is cytotoxic to endothelial cells and smooth muscle cells5. Can induce endothelial cell dysfunctionPathogenic events in Atherosclerosis* Endothelial Injury - | vascular permeability leukocyte adhesion and thrombosis* Accumulation of lipoproteins (Mainly LDL and its oxidized forms) in the vessel wall* Monocyte adhesion to the endothelium - followed by migration into the intima and transformation into macrophages and foam cells* Plaelet adhesion* Factor release from activated platelets, macrophages and vascular wall-cells, inducing smooth muscle cell recruitment either from the media or from circulating precursors* Smooth muscle cell proliferation and ECMproduction* Lipid accumulation both extracellulary and within cells (macrophages and smooth muscle cells)Apo - B- 100 is responsible for the recognition of LDL receptor sites* Most important function of LDL is to supply cholesterol to this extrahepatic tissues. The LDL particles bind to the specific receptor pits (Identified as glycoprotein) on the cell membraneDeficiency of LDL receptors is observed in Type Ila hvperbetalipoproteinemia this disorder is associated with a very high risk of atherosclerosis (particularly coronary artery)IMPORTANT POINTS* Most common of ascending aortic aneurysm - cystic medial necrosis* Most common cause of descending aortic aneurysm and aneurysm aortic arch - Atherosclerosis.* Raised serum level of lipoprotein (a) is a predictor of Atherosclerosis (coronary and cerebro vascular disease)* In atherosclerosis, LDL is present in the LDL monocyte* In atherosclerosis, Increased LDL in monocytes- macrophages due to- LDL receptors on the macrophages* Most common cause of peripheral limb ischaemia in India is Atherosclerosis* Best predictor for future risk of cardiovascular events is hs CRP* Test for reversible cardiac ischemia is - Thallium scan* Most common change in atherosclerotic vessel is - Dystrophic calcification
Oxidised LDL
HDL
VLDL
Glycerides
Blood Vessels