MyFatDog
VLDL, LDL, HDL
VLDL
VLDL stands for Very Low Density Lipoprotein. VLDL is made in the liver and it delivers mainly fat
(triglyceride) and some cholesterol to different part of the body. Once its done its job some VLDL
is taken up by the liver and the remainder is converted into LDL.
(triglyceride) and some cholesterol to different part of the body. Once its done its job some VLDL
is taken up by the liver and the remainder is converted into LDL.
LDL
LDL stands for Low Density Lipoprotein. Its main function is to deliver cholesterol to different
parts of the body. Any leftover LDL is eventually removed from blood by the liver by binding to
LDL receptors in the liver.
parts of the body. Any leftover LDL is eventually removed from blood by the liver by binding to
LDL receptors in the liver.
VLDL and LDL play very important roles of delivering fat and cholesterol to different parts of the
body. However, too much VLDL and LDL can harm you. Normally a small amount of VLDL and LDL
stick to parts of your arteries and are removed by some white blood cells. When VLDL and LDL
cholesterol levels are high, too much VLDL and LDL is removed by white blood cells in these areas
in arteries causing the white cells to activate like they would when they respond to an infection.
The activated white cells release factors that cause other white cells to respond to the same area.
White cells that are loaded with too much cholesterol can't move throughout the body and begin to
accumulate in certain arteries such as those in the heart. Eventually enough white cells accumulate
to form an atherosclerotic plaque which can narrow the artery. If this happens in the arteries in the
heart it can lead to a heart attack. If it happens in arteries in the brain it can lead to a stroke.
body. However, too much VLDL and LDL can harm you. Normally a small amount of VLDL and LDL
stick to parts of your arteries and are removed by some white blood cells. When VLDL and LDL
cholesterol levels are high, too much VLDL and LDL is removed by white blood cells in these areas
in arteries causing the white cells to activate like they would when they respond to an infection.
The activated white cells release factors that cause other white cells to respond to the same area.
White cells that are loaded with too much cholesterol can't move throughout the body and begin to
accumulate in certain arteries such as those in the heart. Eventually enough white cells accumulate
to form an atherosclerotic plaque which can narrow the artery. If this happens in the arteries in the
heart it can lead to a heart attack. If it happens in arteries in the brain it can lead to a stroke.
HDL
HDL stands for High Density Lipoprotein. It is initially made in the liver and intestine as a flat
empty particle. It travels around the body picking up excess cholesterol. When it starts to get full
it can get emptied in two ways:
empty particle. It travels around the body picking up excess cholesterol. When it starts to get full
it can get emptied in two ways:
1) One way is to recycle some of the cholesterol by transferring it to VLDL and LDL. The VLDL
and LDL then carry the cholesterol back to the liver. This transfer is handled by a special protein
called cholesteryl ester transfer protein or CETP.
and LDL then carry the cholesterol back to the liver. This transfer is handled by a special protein
called cholesteryl ester transfer protein or CETP.
2) The other way is to take it to the liver which will dispose of it in the gut. Once the HDL particle
is emptied it can go back around the body and pick up more cholesterol.
is emptied it can go back around the body and pick up more cholesterol.
This response to high levels of VLDL and LDL is thought to be very slow and may take years or
decades. Some people have a rare disease, called Homozygous Familial Hyper-cholesterolemia or
HoFH that prevents most of their LDL from being recognized and removed from the blood by the
liver. These people can have cholesterol levels greater than 1,000 mg/dl. If untreated, these
individuals rapidly develop atherosclerosis and can have a heart attack before they are 10 years
old! Here's a news article about an 11 year old with undiagnosed HoFH that died.
decades. Some people have a rare disease, called Homozygous Familial Hyper-cholesterolemia or
HoFH that prevents most of their LDL from being recognized and removed from the blood by the
liver. These people can have cholesterol levels greater than 1,000 mg/dl. If untreated, these
individuals rapidly develop atherosclerosis and can have a heart attack before they are 10 years
old! Here's a news article about an 11 year old with undiagnosed HoFH that died.
Copyright © 2008-2012 John Millar. All rights reserved.
