Which statement best describes the role of High Density Lipoproteins?

• A. They transport cholesterol to tissues for storage.
• B. They transport cholesterol from the liver to the tissues for distribution.
• C. They facilitate the formation of LDL particles.
• D. They transport cholesterol from tissues to the liver for breakdown.

Answer: (D)

High-density lipoproteins handle reverse cholesterol transport. They pick up cholesterol from peripheral tissues (including arterial walls) and return it to the liver so it can be broken down and eliminated. This process is aided by enzymes like LCAT, which esterify free cholesterol to form a core of cholesteryl esters inside the HDL particle, enabling efficient transport. The liver then takes up this cholesterol, often via scavenger receptor B type I, completing the cycle.

This description matches the idea that HDL moves cholesterol from tissues to the liver for breakdown and excretion. In contrast, transporting cholesterol to tissues for storage is the role of other lipoproteins (like LDL/VLDL), and HDL does not primarily facilitate the formation of LDL particles.