Lipo proteins

Normal and Therapeutic Nutrition 3(2+1)
Lesson 26:Cardiovascular and atherosclerosis – causes, symptoms

Lipo proteins

Since lipoproteins are the major transport forms of lipids in the blood, an increase in one or more of these plasma lipoproteins creates a condition called hyper lipoproteinemia which is a risk factor for heart disease. Lipoproteins are formed in the intestinal wall after the ingestion of a meal. They have a high triglyceride content and are cleared from the blood by lipoprotein lipase. The liver also synthesizes lipoproteins from endogenous fat sources.

The various lipo proteins are:


  • Chylomicrons – produced from exogenous fat and consisting of a large percentage of triglycerides.
  • Very low density lipoproteins (VLDL), formed from endogenous fats in the liver also contain more of lipids and less of proteins.
  • Intermediate density lipoproteins (IDL) deliver endogenous triglycerides to the cells for their use.
  • Low Density Lipoprotein (LDL) carry two thirds of the plasma cholesterol. Since LDL carries more cholesterol to the cell, it is the main agent of concern.
  • High Density Lipoprotein (HDL) carries less cholesterol and more protein and is also formed in the liver from endogenous fat sources. It carries cholesterol from the tissues to the liver for breaking down and excretion and therefore higher levels of HDL are considered cardio protective.

Apo proteins

Apo proteins refer to the protein part of a combined protein. Apo proteins are mostly synthesized by the liver and few by intestinal mucosa. Defects in the synthesis of these Apo proteins can lead to a disturbance in the serum lipoprotein level. Most of these changes are familial and rare. For example in a deficiency of apoprotein A, HDL cannot be formed and cholesterol accumulates in the tissues. Similarly Apo lipoprotein E deficiency is characterized by low LDL concentration and non formation of chylomicrons. The cholesterol rich remnants of chylomicrons accumulate in the blood and cause lipid deposits in the skin called xanthomas.

Last modified: Tuesday, 25 October 2011, 5:20 AM