Which lipoprotein particle carries the majority of cholesterol in the bloodstream and is commonly elevated in atherosclerosis?

• A. High Density Lipoprotein (HDL)
• B. Chylomicron
• C. Low Density Lipoprotein (LDL)
• D. Very Low Density Lipoprotein (VLDL)

Answer: (C)

Lipoproteins transport cholesterol in the blood, and the particle that carries the largest share of plasma cholesterol and tends to be elevated in atherosclerosis is Low Density Lipoprotein. LDL's main role is to deliver cholesterol to cells throughout the body via LDL receptors. When there is excess LDL, or when it becomes oxidized in the arterial wall, macrophages take up the cholesterol and form foam cells, initiating fatty streaks and plaque buildup in arteries.

In contrast, HDL is involved in reverse cholesterol transport, pulling cholesterol from tissues back to the liver for disposal and is generally protective against atherosclerosis. Chylomicrons mainly shuttle dietary triglycerides from the intestine, with little cholesterol content in the fasting state, while VLDL carries triglycerides from the liver and becomes LDL as its triglycerides are removed.