Intermediate-density lipoproteins belong to the lipoprotein particle family and are formed from the degradation of very low-density lipoproteins. IDL is one of the five major groups of lipoproteins (chylomicrons, VLDL, IDL, LDL, HDL) which enable fats and cholesterol to move within the water based solution of the blood stream. Each native IDL particle consists of protein that encircles various fatty acids; enabling, as a water soluble particle, these fatty acids to travel in the aqueous blood environment as part of the fat transport system within the body. Their size is generally 25 to 35 nm in diameter and they primarily contain a range of triacylglycerols and cholesterolesters. They are cleared from the plasma into the liver by receptor-mediated endocytosis, or further degraded to form LDL particles.
Generally, IDL, somewhat similar to low-density lipoprotein (LDL), transports a variety of triglyceride fats and cholesterol and, like LDL, can also promote the growth of atheroma.
