Which lipoprotein class is the major carrier of cholesterol away from tissues?

Which lipoprotein class is the major carrier of cholesterol away from tissues?

• A. LDL
• B. HDL
• C. VLDL
• D. Chylomicrons

Answer: (B)

This item tests reverse cholesterol transport. The lipoprotein class that acts as the major carrier of cholesterol away from peripheral tissues is high-density lipoprotein (HDL). HDL scavenges excess cholesterol from cells in tissues (including macrophages and arterial wall cells) and transfers it to the liver for excretion or recycling. As HDL matures, enzymes like LCAT esterify cholesterol, forming cholesteryl esters that move into the core of the particle, and hepatic uptake of these esters occurs via receptors such as SR-BI. This pathway contrasts with other lipoproteins that primarily deliver cholesterol to tissues—chylomicrons from the intestine, VLDL from the liver, and LDL to peripheral cells—so HDL is the key player in removing cholesterol from tissues.

This item tests reverse cholesterol transport. The lipoprotein class that acts as the major carrier of cholesterol away from peripheral tissues is high-density lipoprotein (HDL). HDL scavenges excess cholesterol from cells in tissues (including macrophages and arterial wall cells) and transfers it to the liver for excretion or recycling. As HDL matures, enzymes like LCAT esterify cholesterol, forming cholesteryl esters that move into the core of the particle, and hepatic uptake of these esters occurs via receptors such as SR-BI. This pathway contrasts with other lipoproteins that primarily deliver cholesterol to tissues—chylomicrons from the intestine, VLDL from the liver, and LDL to peripheral cells—so HDL is the key player in removing cholesterol from tissues.