There is a lot of controversy going on role of cholesterol as well as on a group of drugs known as STATINS.Many have dubbed this drug as useless while others have branded it potentially harmful.So, there is a lot of confusion as many research papers which support the use of statins are said to be sponsored by vested interest in pharma industry.Yet the main stream medical fraternity is sticking to its previously held position that statins have cardio protective as well as a very positive and beneficial effect in cases of stroke. So let us try to understand the whole thing in a simple way.
WHAT is cholesterol,it is a lipid molecule,which is integral part of structure and function of of human cells.It is an essential constituent of cell membrane,it regulates membrane fluidity, and is precursor of steroid hormones, such as Cortisol,Progesteron,Testosteron,Oestrogen or Aldosterons and bile acids(essential for digestion ) .It has also been implicated in cell signalling system.
There are two sources of cholesterol. 1. Its synthesis by the liver (endogenous ). 2. Derived from the lipids included in the diet.(exogenous ). Endogenous production provides (900mgs/day ) about majority of required cholesterol ,whereas dietary intake provides about 300mgs/day.The synthesised cholesterol from liver is transported in blood stream to peripheral tissues by LDL lipoproteins and HDL lipoprotein carry it from blood stream to liver where it is excreted.
How statins work, There is an enzyme that catalyses the biosynthesis of cholesterol in the liver, HMG-Co A ,and statins due to its structural homology to HMG-CoA attaches itself to hepatocytes leading to a decrease in the cholesterol content of the hetatocytes.
Biosynthesis of cholesterol is directly regulated by cholesterol levels.hence an increase in cholesterol levels due to higher intake from diet leads to decrease in its production and vice versa.
When cholesterol synthesis is blocked by the action of statins,hepatic cells respond by producing more HMG-CoA and increasing the number of LDL receptors on the surface of hepatocytes,enhancing LDL uptake from blood stream, as a result serum LDL level falls.Therefore,cholesterol lowering effects of statins are mainly the consequence of clearance of LDL from serum rather than reduction of cholesterol synthesis.
Apart from cholesterol lowering effect, there are other actions of statin,which may be talked at some other time as post is getting lengthy .This post is neither for or against statins, as a lot remains to be understood.
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