What does LDL Cholesterol Do ?
Generally, LDL transports cholesterol and triglycerides away from cells and tissues that produce more than they use, towards cells and tissues which are taking up cholesterol and triglycerides.
Low density lipoprotein (LDL) refers to a class and range of lipoprotein particles, varying in their size and contents, which carry cholesterol in the blood and around the body, for use by cells. It is the final stage of VLDL (very low density lipoprotein) which is produced by the liver. The LDL contains the apoprotein B-100 (Apo B-100) among it plasma lipids. It is commonly referred to as "bad cholesterol" due to the link between high LDL levels and cardiovascular disease.
LDL Cholesterols Role in disease
Because LDL transports cholesterol to the arteries, increased levels are associated with atherosclerosis, and thus myocardial infarctions, strokes and peripheral vascular disease. This is why cholesterol inside LDL lipoproteins is called bad cholesterol. Still, it is not the cholesterol that is bad; it is instead how and where it is being transported, and in what amounts over time.
Increasing evidence has revealed that the concentration and size of the LDL particles more powerfully relates to the degree of atherosclerosis progression than the concentration of cholesterol contained within all the LDL particles. Having low concentrations of large LDL particles is the healthy pattern. Conversely, high concentrations of small LDL particles, despite the same total cholesterol levels correlates with much faster growth of atheroma and progression of atherosclerosis.
LDL is formed as VLDL lipoproteins, which lose triglyceride through the action of lipoprotein lipase (LPL), and become smaller and denser containing a higher proportion of cholesterol.
A hereditary form of high LDL is familial hypercholesterolemia (FH). Increased LDL is termed hyperlipoproteinemia type II (after the dated Fredrickson classification).
LDL Cholesterol Levels
Over time, with more clinical research, the recommended levels keep being reduced because LDL reduction, including to abnormally low levels has been the most effective strategy for reducing cardiovascular death rates in large double blind, randomized clinical trials; far more effective than coronary angioplasty/stenting or bypass surgery. |