The Lipid Center of Virginia

What are lipids and lipoproteins and why are they important?

 Lipids are fats that are found in our bloodstream.  The two major types of lipids are cholesterol and triglycerides.  Lipids are used by our bodies in a variety of tissues and for a variety of functions.  Lipids can not dissolve in the bloodstream so they must be carried inside spherical particles called lipoproteins.  There are different types of lipoproteins and each serves a different function:

 LDL (low density lipoprotein):  These particles are mainly waste products carrying cholesterol and triglycerides to our liver for removal from the blood stream.  These are the so-called “bad” lipoproteins as they have the capability of entering the artery lining, sticking and releasing their lipids, causing atherosclerosis and subsequent blockages (plaques).  The more LDLs you have in your blood stream, the more likely you will get plaques.  Plaques can rupture, causing a heart attack or stroke.

 HDL (high density lipoprotein): These particles also carry cholesterol and triglycerides and can also enter the arterial lining.  They are called the “good” lipoproteins as they are capable of carrying away some of the cholesterol that has deposited in the artery lining.  You want a lot of these.

 There are also VLDLs, IDLs and Chylomicrons all of which serve specific functions.

 Of importance is that we now know the risk of heart attacks and strokes is correlated more with how many LDLs (LDL-p) we have in our bloodstream as opposed to how much cholesterol is in our LDLs (LDL-c).  Standard lipid profiles only tell us how much cholesterol and triglycerides are in our lipoproteins, not how many lipoproteins we have!  You need to know how many lipoproteins you have in order to really know your risk of future cardiovascular events.  Our advanced lipid testing at CALM gives you this information.


            LDL-p:  the number of LDL particles in the bloodstream

            LDL-c:  the amount of cholesterol in LDLs

            HDL-p:  the number of HDL particles

            HDL-c:  the amount of cholesterol in HDLs

            Triglycerides: the amount of triglycerides in all lipoproteins (LDL, HDL, IDL, VLDL and chylomicrons)

            Total Cholesterol:  the amount of cholesterol in all lipoproteins

How Do Cholesterol Medications Work?

The lower the number of LDL particles in the blood, the lower the risk of heart attacks.  LDL particles are removed from the blood stream by LDL receptors that reside on liver cells, so the more LDL receptors, the better. The two most powerful cholesterol lowering medications are statins and PCSK9 inhibitors. These medications work by increasing the number of working LDL receptors.  

Statins block the production of cholesterol within the liver, which in turn sets off cellular mechanisms that cause the liver to make more LDL receptors.  PCSK9 inhibitors are monoclonal antibodies that bind to and inactivates a protein called PCSK9.  The PCSK9 protein circulates in the blood and causes the degradation of LDL receptors.  By blocking the PCSK9 protein with an antibody, the number of LDL receptors is increased.

What is the role of inflammation?

Inflammation is a complicated process that involves the activation of our immune system.  To produce atherosclerosis, not only do LDL particles have to stick to our artery lining but our immune system has to be activated to attack them.  Testing for inflammation is important in developing an overall prevention plan.