ROLE OF OXIDIZED LIPOPROTEINS IN PLAQUE FORMATION IN ARTERIAL WALL:
1) Monocytes adhere to endothelial cells and squeeze through endothelial cells. Monocytes become tissue macrophages and move to into subendothelium.
2) Macrophages consume excess modified (oxidized) lipoprotein, becoming foam cells.
3) Foam cells accumulate, releasing growth, factors that stimulate proliferation of smooth muscle and calcification of plaque.
LIPID COMPOSITION OF THE DIET AFFECTS SERUM CHOLESTEROL
There are at least four components that can be identified as having an effect on serum cholesterol: cholesterol itself, polyunsaturated fatty acids (PUFA), saturated fatty acids (SFA), and fiber. It would appear obvious that the more cholesterol one eats, the higher the serum cholesterol would be, However, cholesterol synthesis is tightly regulated via feedback control at the hydroxymethylglutaryl CoA reductase step so decreases in dietary cholesterol have relatively little effect on serum cholesterol levels. One can obtain a more significant reduction in cholesterol and triachylglycerol levels by increasing the ratio of PUFA/SFA in the diet. Finally, some plants fibers, especially the water soluble fibers, appears to decrease cholesterol levels significantly. While the effects of various fats in the diet can be dramatic, the biochemistry of their action is still uncertain. Saturated fats have been shown to inhibit receptor-medicated uptake of low density lipoprotein (LDL), but the mechanism of this effect is obviousely complex. Palmitic acid (saturated, C16) raises cholesterol levels while stearic acid acid (saturated, C18) is neutral. Polyunsaturated fatty acids lower both LDL and HDL cholesterol levels, while oleic acid (monounsaturated, C18) appears to lower LDL without affecting high density lipoprotein (HDL) levels. Further more, the W-3 and W-6 polyunsaturated fatty acids have slightly different effects on lipid profiles. However, these mechanistic complexities do not significantly affect dietary recommencations. Most foods high in saturated fats contain both palmitic and stearic acid, and are still atherogenic. The data showing that oleic acid lowers LDL levels mean olive oil, and possibly peanut oil, may be considered as beneficials as the polyunsaturated oils.
LDL Cholesterol Reducing Cholesterols
Metabolism of LDL SummaryFat Intake Reference
Recommended Health Fat .......
Table of Contents Introduction Saturated Fat LDL Cholesterol�