Which cells become foam cells after taking up LDL in arterial walls?

Which cells become foam cells after taking up LDL in arterial walls?

• A. Endothelial cells
• B. Platelets
• C. Smooth muscle cells
• D. Macrophages

Answer: (D)

Foam cells come from macrophages that ingest modified LDL in the arterial wall. When macrophages encounter LDL that has been altered (often oxidized) during inflammation and atherogenesis, they take it up through scavenger receptors. Unlike normal cells, macrophages don’t downregulate cholesterol uptake the way other cells might, so they accumulate cholesterol esters inside lipid droplets. This buildup gives the macrophages a foamy, lipid-laden appearance under the microscope and helps form the fatty streaks that initiate atherosclerotic plaques. Endothelial cells line the vessel lining and aren’t the lipid-laden foam cells; platelets aren’t known for accumulating lipids to become foam cells; smooth muscle cells can become lipid-laden to some extent, but the classic and most characteristic foam cells in arterial walls are macrophages.

Foam cells come from macrophages that ingest modified LDL in the arterial wall. When macrophages encounter LDL that has been altered (often oxidized) during inflammation and atherogenesis, they take it up through scavenger receptors. Unlike normal cells, macrophages don’t downregulate cholesterol uptake the way other cells might, so they accumulate cholesterol esters inside lipid droplets. This buildup gives the macrophages a foamy, lipid-laden appearance under the microscope and helps form the fatty streaks that initiate atherosclerotic plaques. Endothelial cells line the vessel lining and aren’t the lipid-laden foam cells; platelets aren’t known for accumulating lipids to become foam cells; smooth muscle cells can become lipid-laden to some extent, but the classic and most characteristic foam cells in arterial walls are macrophages.