How is cholesterol transported into the body?

Cholesterol and other fats are carried in your bloodstream as spherical particles called lipoproteins. The two most commonly known lipoproteins are low-density lipoproteins (LDL) and high-density lipoproteins (HDL).

How does LDL deliver its cholesterol to the cells?

LDL receptors are inserted into the plasma membrane and diffuse freely until they associate with clathrin-coated pits. When LDL receptors bind LDL particles in the bloodstream, the clathrin-coated pits are endocytosed into the cell. Vesicles containing LDL receptors bound to LDL are delivered to the endosome.

What transports cholesterol to peripheral tissues?

HDL serves as a chemical shuttle that transports excess cholesterol from peripheral tissues to the liver. This pathway is called the reverse cholesterol transport (RCT) system. In this system, plasma HDL takes up cholesterol from the peripheral tissues, such as fibroblasts and macrophages.

What is the function of the LDL?

Low-Density Lipoproteins (LDL) LDL is responsible for carrying cholesterol to cells that need it. Elevated LDL levels are associated with an increased risk of cardiovascular disease.

Where does HDL transport cholesterol in the body?

On the other hand, high density lipoprotein (HDL) transports cholesterol from peripheral tissues including atheroma to liver, subsequently to bile and feces via the so-called reverse cholesterol transport (RCT) pathway (Figure 3.1).

How is cholesterol exported to the peripheral tissues?

Cholesterol is exported to the peripheral tissues in LDL and VLDL. About 70 percent of the cholesterol molecules in LDL are esterified with a fatty acid (for example, palmitate) on the OH group (at Carbon 3; see Figure 1 ). Cells take up cholesterol from the LDL by means of LDL receptors in the outer cell membrane.

What’s the difference between LDL and HDL cholesterol?

LDL is known as “bad” cholesterol because it delivers cholesterol to tissues and is strongly associated with the buildup of artery-clogging plaque. High-density lipoprotein (HDL) particles are called “good” cholesterol because some of them remove cholesterol from circulation and from artery walls and return it to the liver for excretion.

How is LDL cholesterol removed from the circulation?

The capability of LDL receptors to remove LDL cholesterol from the circulation can rationalize these clinical observations. If little cholesterol is available in the diet, the cells of the peripheral tissues respond by up‐regulating the number of LDL receptors on the cell surface.