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The Cholesterol Play

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By emiller8988
January 21, 2005

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There is no such thing as bad cholesterol. There is no such thing as good cholesterol. Cholesterol is a brick. This brick is used for synthesis of hormones, building cell walls, building nerve tissue, and is generally one of the vital building blocks of life. Under normal circumstances 80 to 90% of the cholesterol circulating in your blood at any time, is manufactured by your liver. It doesn't come from your diet. So, if cholesterol is a brick, your liver is a brick factory. The brain, kidney, heart, adrenal glands, etc. are the building sites of the body. The great architect of the body, in his genetic wisdom, has to figure out how to get those cholesterol bricks from the factory (liver) to various building sites. Unfortunately, cholesterol is a lipid-based substance. The highway system of the body is, of course, the circulation. Unfortunately, the circulatory system is water-based and cholesterol will not dissolve in the water. He had to figure out a way to dissolve the cholesterol in the blood so it can get from the brick factory (the liver) to the building sites of the body. We'll do that by coating the cholesterol molecule with a protein molecule. This cholesterol-protein complex is then soluble in water very much like a soap is soluble in water. A soap molecule has a portion that is soluble in water and a second portion that is soluble in grease or fat so, I hate to say it.... soap is "bi"... it goes both ways. Now, the protein molecule that transports cholesterol from the brick factory to the building site is rather light and the chemical bond between the protein in the cholesterol is tenuous. It has to be that way, the protein transport molecule has to be able to drop the cholesterol off as it passes by the chosen building site. So, the transport protein is light and a bit fumble fingered. It will occasionally fumble that cholesterol brick in unintended locations. The combination of the transport protein and cholesterol is called low-density lipo-protein or LDL for short. As those bricks of cholesterol tend to be fumbled in the same general spots, a pile of bricks will begin to build up on the side of the circulatory road (a cholesterol plaque will begin to form). The great architect, in his wisdom, realized that this would occur. So he set into the circulation a scavenger protein, a big bruising protein that looks for free cholesterol molecules. As it finds them it gathers them up, holds tightly, and carries them back to the liver to be reprocessed. The combination of the scavenger protein and cholesterol is called high-density lipo-protein or HDL for short. So, we've got the light, fumble fingered protein (LDL) that transports bricks from the factory to the building sites, and we have the heavy scavenger protein (HDL) that looks for dropped bricks, picks them up, binds them tightly, and returns them to the factory

In my mind's eye. When I visualize LDL, I see the Three Stooges driving a delivery truck, careening around curves in the circulation, dropping a cholesterol brick here and there on their way to the building site. When I visualize HDL, I see Dudley Do-Right with a firm grip on the wheel, driving slowly down the road, looking for cholesterol messes to clean up. Now, if you have lots and lots of Dudley Do-Right's driving carefully down the circulatory highway, it doesn't much matter how much cholesterol gets dropped. It's all going to get picked up. On the other hand, if there are very few of those Dudley Do-Right's driving through the circulation of your body, it won't be long before you have a pile of bricks blocking the road (an obstructing cholesterol plaque).

So you see, there is no good or bad cholesterol... cholesterol is a brick. The "good and bad" are the ways cholesterol is being carried in the blood stream... a light fumble fingered transport protein.... or a heavy, hands like a vice, scavenger protein.

There's one last item. Have you ever seen what a little drop of cooking oil does when it is placed in a glass of water. It won't sit still. It floats around like it has a little motor. Finally, it zips over to the side of the glass and clings to the edge of the glass for dear life. That is how a free cholesterol molecule acts when it is dropped into the river of our circulatory system. It zips over to blood vessel wall and does everything it can chemically do to get out of that water. In the process, it tries to dissolve itself directly into the blood vessel wall. Hopefully, while this is occurring, one of those Dudley Do-Right HDL's will come along and grab it up to carry it back home. If not, the cholesterol molecule starts to dissolve into the side of the blood vessel wall, starts a cholesterol plaque, and begins an inflammatory process. In other words, it irritates the side of the blood vessel wall. It turns out that there is a marker for this process of inflammation in the body. While it's not a perfect marker for inflammation in the blood vessels... it does pretty well and elevated levels are a sure sign of increased cardiovascular risk. That marker is called C-reactive protein. The lower it is, the better... the higher it is, the worse. Inflammation is the body's version of rust... a sort of tearing down, wearing out process. It has its place in the body... but NOT in the sides of our blood vessel walls.

Now we have our four most important actors in the drama of cardiovascular health.
1- the brick... played by the cholesterol molecule.
2- Dudly Do-Right... played by the high density scavenger protein.
3- the three stooges... played by the low density transport protein.
4- rust... played by C-Reactive protein, the marker of inflammation.

Now... next post I going to go through the way this little story is being acted out in the world of pharmaceuticals and how Pfizer and others have decided to play their parts in this little drama. But right now... my fingers are tired :) and the sun has come out.

e

Part 2

Part 3


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